Journal of Composites Science doi: 10.3390/jcs8030106
Authors: Ghane Moradkhani Jacopo Profili Alex Destrieux Mathieu Robert Gaétan Laroche Saïd Elkoun Frej Mighri Pascal Y. Vuillaume
This research centered on enhancing the mechanical properties of sustainable composite materials made from short flax fibers. Challenges associated with fiber–matrix adhesion and moisture absorption were systematically addressed. A water–alginate pre-treatment, combined with plasma modification, was employed to stabilize the fibers, ensuring their optimal preparation and improved compatibility with biopolymers. A thorough investigation of the effect of the plasma modulation using a duty cycle (DC) was conducted, and extensive physicochemical and mechanical analyses were performed. These efforts revealed conditions that preserved fiber integrity while significantly improving surface characteristics. Techniques such as optical emission spectroscopy (OES), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and Dynamic Mechanical Analysis (DMA) were utilized, providing a comprehensive understanding of the transformations induced by the plasma treatment. The findings underscored the critical role of alginate and precise plasma settings in enhancing the mechanical properties of the composites. Ultimately, this study made a substantial contribution to the field of eco-friendly materials, showcasing the potential of short flax fibers in sustainable composite applications and setting the stage for future advancements in this area.
]]>Journal of Composites Science doi: 10.3390/jcs8030107
Authors: Sourav Banerjee Vahid Tavaf Mustahseen M. Indaleeb
This article presents a concept, materials, and methods to devise a Bond Quality Index (BQI) for assessing composite bond quality, approximately correlating to the respective bond strength. Interface bonding is the common mechanism to join two composite structural components. Ensuring the health and quality of the bond line between two load-bearing composite structures is crucial. The article presents the classification and data-driven distinction between two types of bond lines between similar structural components. The interface bonds in composite plates were prepared using polyester peel ply and TX-1040 nylon peel ply. For all the plates, ultrasonic inspection through scanning acoustic microscopy (SAM) (>10 MHz) was performed before and after localized failure of the plate by impinging energy. Energy was impinged 0–10 J/cm2 of in the 16-ply plates, and 0–25 J/cm2 were impinged in 40-ply plates. Followed by bond failure and SAM, a new parameter called the Bond Quality Index (BQI) was formulated using ultrasonic scan data and energy data. The BQI was found to be 0.55 and 0.45, respectively, in plates with polyester peel ply and TX-1040 nylon peel ply bonds. Further, in 40-ply plates with polyester peel ply resulted in a BQI equivalent to 3.49 compared to 0.75 in plates with a TX-1040 nylon peel ply bond. Currently, the BQI is not normalized; however, this study could be used for AI-driven normalized BQIs for all types of bonds in the future.
]]>Journal of Composites Science doi: 10.3390/jcs8030105
Authors: Jurga Šeputytė-Jucikė Sigitas Vėjelis Saulius Vaitkus Agnė Kairytė Arūnas Kremensas
The purpose of this study was to evaluate the moisture and flammability characteristics of lightweight concrete with different aggregates and different amounts of cement according to different criteria. The moisture properties of the specimens were evaluated by the coefficient of water absorption due to capillary action, short-term water absorption, and water vapour permeability. Short-term water absorption correlated with the density of the specimens, and capillary absorption was evaluated depending on the soaking time, amount of cement, and type of lightweight aggregate. The values of the water vapour diffusion resistance factor were estimated based on the amount of cement, the type of lightweight aggregate, the density, and the porosity. The porosity correlated with the amount of cement and the type of lightweight aggregate. The flammability properties of concrete with lightweight aggregate were evaluated by several methods, such as the single flame source test, the single burning item test, and the non-combustibility test. After assessing the flammability characteristics, a structure analysis of the samples was specifically performed to assess the processes that occur during the combustion of lightweight concrete. It was found that short-term water absorption depended mainly on the density, capillary absorption on the amount of cement, and the water vapour diffusion resistance factor, flammability, and thermal stability of lightweight concrete on the type of granules.
]]>Journal of Composites Science doi: 10.3390/jcs8030104
Authors: Alicia Rosales Hugo Mandujano José Antonio Cervantes-Chávez Karen Esquivel
Film applications’ recent advances in the alimentary industry mainly focus on extending product shelf life. Researchers have investigated the use of nanomaterials as active packaging to shield food product contents from the outside elements and prevent bacterial development. In this context, the use of sonochemistry energy offers a friendly and efficient opportunity to obtain this kind of film. However, access to an ultrasonic homogenizer is limited because of the cost and accessories. In this work, a self-cleaning coating based on the SiO2-TiO2-PDMS composite was obtained by the sol–gel method coupled with indirect sonochemical energy. Two sonication reaction times were used to investigate its impact on the final composite’s chemical, morphological, and antibacterial properties. TEM and SEM techniques indicate an amorphous morphology and superficial cracks in SiO2-TiO2-PDMS films over aluminum foil. At the same time, AFM reveals a rise in rugosity with a value of Ra = 18.7 ± 2.47 nm, increasing the sonochemical reaction time. Non-significative changes by FTIR-ATR analysis were observed. The antibacterial evaluation was conducted, and the results indicate that both composites exhibited superior effectiveness. Specifically, the S40 film demonstrated a significant reduction in the growth of Gram-negative cells (E. coli, P. putida, and P. aeruginosa), with reductions ranging from 50% to 95%. In contrast, the reduction in Gram-positive cells (S. aureus) was less than 10%. These findings underscore the potential application of the SiO2-TiO2-PDMS film as active packaging.
]]>Journal of Composites Science doi: 10.3390/jcs8030103
Authors: Mustafa Alhusain Adil Al-Mayah
Gripping prestressed carbon fiber-reinforced polymers (CFRPs) in structural strengthening applications is challenging due to CFRPs’ susceptibility to lateral loading. This paper presents a reliable and reusable wedge anchorage for gripping CFRP plates that are 50 mm wide and 1.2 mm thick. The cylindrical anchorage, which is 75 mm long and 76.2 mm in diameter, consists of an external steel barrel, two internal steel wedges, and two soft copper sleeves. The barrel-wedge interface is designed using an innovative arc–linear configuration, through which the desired stress distribution is attained, preventing stress concentration and the premature failure of the CFRP plate. The wedge anchorage was experimentally tested by applying a displacement-controlled tensile load of 0.6 mm/min until the complete fracture of the CFRP plate. The anchorage’s performance was examined under distinct installation conditions by applying different presetting levels: high (40–120 kN) and low (hammering) presetting. It was observed that the anchorage successfully prevented CFRP premature failure in all tests by achieving an average tensile loading of 172.3 (±5.7) kN, exceeding its reported tensile strength of 168 kN (2800 MPa). Minor CFRP displacements of 6.26 (±0.75) mm and 3.33 (±0.16) mm were recorded under low and high presetting levels, respectively. Similarly, the CFRP slippage relative to the wedges for the low and high presetting tests was only 1.18 (±0.75) mm and 0.33 (±0.15) mm, respectively. Also, only minor scratches were observed in the wedge–barrel interface, indicating the absence of extensive plastic deformation.
]]>Journal of Composites Science doi: 10.3390/jcs8030102
Authors: Yulia V. Tertyshnaya Anastasia N. Skorokhodova Anastasia Yu. Anpilova Anatoliy A. Olkhov
Presently, modern trends focused on eco-friendly “green” technologies are increasing the widespread use of biodegradable polymers and polymer composites in agricultural production. In this work, non-woven materials, polylactide/natural rubber (PLA/NR) composites with a different natural rubber content, were used as substrates for growing purple basil (Ocimum basilicum L.) in the multisoil compound in a phytochamber. It was shown that non-woven PLA/NR fabrics stimulate the growth and development of purple basil plants during the growing season. Compared to the control sample, the germination and biometric indicators of basil were higher when using PLA/NR substrates. The production of basil’s photosynthetic pigments also increased. While using PLA/NR fabrics with a rubber content of 10 and 15 wt.%, the number of chlorophyll a was enhanced by 1.8–2.2 times and chlorophyll b by 2.5–3.2 times. In the process of the hydrolytic and enzymatic degradation of the polymer matrix, organic compounds are formed that provide additional nutrition for basil plants. Non-woven PLA/NR composites became brittle after the experiment. The PLA/NR morphology, structure, and rheological properties changed, which indicates the course of biodegradation processes in the polymer matrix.
]]>Journal of Composites Science doi: 10.3390/jcs8030101
Authors: Lucas Onghero Marcelo Tramontin Souza Daniel Cusson Wellington Longuini Repette
High-performance concrete (HPC) is widely used in infrastructure for its durability and sustainability benefits. However, it faces challenges like autogenous shrinkage, leading to potential cracking and reduced durability. Fiber reinforcement offers a solution by mitigating shrinkage-induced stresses and enhancing concrete durability. In this sense, this study investigates the use of glass microfibers to mitigate autogenous shrinkage and early-age cracking in high-strength self-compacting concrete. Samples were prepared with two water-to-binder ratios (w/b): 0.25 and 0.32; and three glass microfiber contents: 0.20%, 0.25%, and 0.30 vol.%. The concrete mixtures were characterized in the fresh state for slump flow and in the hardened state for compressive strength, static, and dynamic Young’s modulus. Unrestrained and restrained shrinkage tests were also conducted in the seven days-age. The findings revealed that glass microfibers reduced the workability in mixtures with lower slump flow values (w/b of 0.25), while less viscous mixtures (w/b of 0.32) exhibited a slight improvement. Compressive strength showed a proportional enhancement with increasing fiber contents in concretes with a w/b ratio of 0.32. A contrasting trend emerged in concretes with a w/b ratio of 0.25, wherein strength diminished as fiber additions increased. The modulus of elasticity improved with fiber additions only in the matrix with a w/b ratio of 0.25, showing no correlation with compressive strength results. In shrinkage tests, the addition of glass microfibers up to specific limits (0.20% for a w/b ratio of 0.25 and 0.25% for w/b of 0.32) demonstrated improvements in controlling concrete deformation in unrestrained shrinkage analyses. Concerning cracking reduction in restrained concrete specimens, the mixtures did not exhibit significant improvements in crack prevention.
]]>Journal of Composites Science doi: 10.3390/jcs8030100
Authors: Peyman Sadeghi Ahmad Goli Elham Fini
This paper presents an innovative bituminous composite containing recycled high-density polyethylene (HDPE) as a means of carbon sequestration. To prepare the composite, rejuvenators and recycled HDPE were introduced to reclaimed asphalt pavement (RAP), separately and in combination. To evaluate efficacy of rejuvenators, this study used the following three rejuvenators: waste engine oil (WEO), oleic acid (OA), and vacuum bottom (VB). The performance of the bituminous composite containing HDPE and rejuvenators was evaluated using the indirect tensile fatigue test, the rutting resistance test, the resilient modulus test, and the semi-circular bending test. Results showed that applying a combination of rejuvenators and recycled HDPE improved the resistance to fatigue, rutting, and cracking. Particularly, in terms of improving resistance to cracking, OA proved to be the most effective rejuvenator, followed by WEO and VB. In all bituminous composites studied here, the hybrid application of HDPE and rejuvenator proved to be more effective than the rejuvenator or HDPE alone.
]]>Journal of Composites Science doi: 10.3390/jcs8030099
Authors: Jibing Chen Yanfeng Liu Yong She Yang Yang Xinyu Du Junsheng Yang Yiping Wu
Laser powder bed fusion (L-PBF) additive manufacturing technology can print multi-material parts with multiple functions/properties, and has great potential for working in harsh application environments. However, the metal blank formed by sintering metal powder material with binder added through L-PBF has an obvious porous structure and insufficient mechanical properties, and few studies have been conducted studying this. In this paper, epoxy resin was used to impregnate the blank of porous metal parts formed by L-PBF with iron-based powder material at a certain temperature, and a cross-linked curing reaction was carried out with three kinds of phenolic resin in different proportions under the action of a curing agent, so as to fill the pores and achieve the desired mechanical properties. The characteristic peaks of each group of epoxy resin were characterized using Fourier transform infrared spectroscopy (FT-IR) and H-nuclear magnetic resonance (1H-NMR) spectrums. The microstructure, decomposition temperature, and residue of four epoxy resin dispersion systems were analyzed with a scanning electron microscope (SEM), a thermal gravimetric analyzer (TGA), and derivative thermogravimetry (DTG). The results show that the density of the porous metal parts was obviously improved, the heat resistance temperature of the parts could reach 350 °C, and the tensile strength of the sample after EP2-1 impregnation was increased by 4–6 times after curing at 160 °C for 6 h. Therefore, the use of an epoxy resin dispersion system can increase the porosity of L-PBF porous metal parts, but can also significantly improve their mechanical properties, which can help them to meet the requirements of applications as model materials, biological materials, and functional materials to provide a feasible solution.
]]>Journal of Composites Science doi: 10.3390/jcs8030098
Authors: Anna Stepien Ryszard Dachowski
The subject of this research is sustainable construction and energy saving, which is most reflected in the technological aspects of building construction. This article focuses on single-family buildings, and the subject of this research is hollow blocks (blocks) created as a result of hydrothermal treatment, in this case, autoclaved aerated concrete (AAC) and autoclaved cellular concrete (ACC), both traditional and modified plastics (HIPS). There are two types of materials resulting from hydrothermal treatment: autoclaved sand-lime bricks and autoclaved concrete. Both in the case of ACC and silicates bricks, the basic substrates used during their production are lime, sand and water (cement is also added to cellular concrete). This article presents the methodology of testing the porous structure of autoclaved materials with the use of computed tomography. Aerated concrete (light autoclaved concrete) has a compressive strength of 2–6 MPa. The tests included aerated concrete modified with high-impact polystyrene, commonly known as HIPS. HIPS high-impact polystyrene is a thermoplastic polymer that is obtained by block suspension polymerization of styrene with the addition of synthetic rubber. As a result of polymerization, small particles of polybutadiene remain in the polystyrene male, changing its physical and mechanical properties. The results from the content of air voids in the autoclaved concrete sample were, on average, 52.53%.
]]>Journal of Composites Science doi: 10.3390/jcs8030097
Authors: K. Chinna Maddaiah G. B. Veeresh Kumar R. Pramod
Stir-casting with ultrasonic cavitation produced nano-Al2O3-filled AA7150 matrix composites in this study. The SEM microstructure study shows that all composites include nano-Al2O3 particles with consistent particle sizes and homogenous distribution. EDS and XRD showed no secondary phases or impurities in the composite. Optical microscopy showed intense ultrasonic cavitation effects, and nano-Al2O3 particles caused grain refinement in the AA7150 matrix. The composite’s mechanical characteristics improved when the Al2O3 nanoparticle weight percentage (wt.%) increased. With only 2.0 wt.% nano-Al2O3 particles, the composites yielded 232 MPa, 97.52% higher than the sonicated AA7150 matrix alloy. Multiple models were used to characterize the strength of the AA7150 nano-Al2O3 composite. The findings showed that thermal incongruity, Orowan strengthening, the Hall–Petch mechanism, and load transfer effects contributed the most towards the increased strength of the composite. Increasing the nano-Al2O3 wt.% in the AA7150 matrix improved hardness by 95.08%, yield strength by 90.34%, and sliding wear resistance by 46.52%. This enhancement may be attributed to the combined effects of better grain refinement, enhanced dispersion with dislocation strengthening, and better load transfer between the matrix and reinforcement, which are assisted by the inclusion of reinforcements. This result was confirmed by optical studies.
]]>Journal of Composites Science doi: 10.3390/jcs8030096
Authors: Jayanta Bhusan Deb Jihua Gou Haonan Song Chiranjit Maiti
Materials used in aircraft engines, gas turbines, nuclear reactors, re-entry vehicles, and hypersonic structures are subject to severe environmental conditions that present significant challenges. With their remarkable properties, such as high melting temperatures, strong resistance to oxidation, corrosion, and ablation, minimal creep, and advantageous thermal cycling behavior, ceramic matrix composites (CMCs) show great promise as a material to meet the strict requirements in these kinds of environments. Furthermore, the addition of boron nitride nanoparticles with continuous fibers to the CMCs can offer thermal resistivity in harsh conditions, which will improve the composites’ strength and fracture toughness. Therefore, in extreme situations, it is crucial to understand the thermal resistivity period of composite materials. To forecast the ablation performance of composites, we developed six machine learning regression methods in this study: decision tree, random forest, support vector machine, gradient boosting, extreme gradient boosting, and adaptive boosting. When evaluating model performance using metrics including R2 score, root mean square error, mean absolute error, and mean absolute percentage error, the gradient boosting and extreme gradient boosting machine learning regression models performed better than the others. The effectiveness of machine learning models as a useful tool for forecasting the ablation behavior of ceramic matrix composites was effectively explained by this study.
]]>Journal of Composites Science doi: 10.3390/jcs8030095
Authors: Anton Smirnov Nikita Nikitin Pavel Peretyagin Roman Khmyrov Ekaterina Kuznetsova Nestor Washington Solis Pinargote
The authors would like to highlight the following correction to their published paper [...]
]]>Journal of Composites Science doi: 10.3390/jcs8030094
Authors: Muhammad Ayyan Iqbal Umbreen Us Sahar Alireza Bahrami Noor Yaseen Iffat Siddique
Cement-based composites, as primary construction materials, have undergone significant advancements over the years, yet researchers still face challenges in terms of their durability and impact on the environment. The goal of this research is to develop environmentally friendly cementitious composites blended with sugarcane bagasse ash (SCBA) and reinforce them with multi-walled carbon nanotubes and polypropylene (PP) fibers. Because of the high cost associated with carbon nanotubes (CNTs) and PP fibers, as well as CO2 emission, which affect the economic and environmental aspects of this field, an agricultural waste such as SCBA was introduced in the current study that is both economically and environmentally viable. For this purpose, five mixes were designed by varying the CNTs content whilst keeping the PP fibers and SCBA contents constant at 1.5% and 15% by weight of the binder (ordinary Portland cement + SCBA), respectively. The developed blends were tested for various mechanical and durability properties, i.e., compressive strength, flexural strength, impact strength, water absorption, and ultrasonic pulse velocity. Moreover, the microstructures of the newly developed low-carbon SCBA-based composites reinforced with PP fibers and CNTs were studied through scanning electron microscopy and energy dispersive spectroscopy. The results showed that the developed blends incorporating 15% SCBA, 1.5% PP fibers, and 0.08% CNTs, by weight of the binder, demonstrated the compressive, flexural, and impact strengths as 15.30 MPa, 0.98 MPa, and 0.11 MPa, respectively. The investigated blends proved to be cost-effective and environmentally beneficial, rendering them suitable for utilization in general construction and maintenance works.
]]>Journal of Composites Science doi: 10.3390/jcs8030093
Authors: Florian Mischo Sebastian Schmeer
Continuous fiber reinforced thermoplastics (cFRTP) are one of the most promising lightweight materials. For their use in structural components, reproducible and comparable material values have to be evaluated, especially at high strain rates. Due to their high stiffness and outstanding strength properties, the evaluation of the material behavior at high strain rates is complex. In the presented work, a new tensile specimen geometry for strain rate testing is virtually optimized using a metamodel approach with an artificial neural network. The final specimen design is experimentally validated and compared with rectangular specimen results for a carbon fiber reinforced polycarbonate (CF-PC). The optimized specimen geometry leads to 100% valid test results in experimental validation of cross-ply laminates and reaches 9% higher tensile strength values than the rectangle geometry with applied end tabs at a strain rate of 40 s−1. Through the optimization, comparable material parameters can be efficiently generated for a successful cFRTP strain rate characterization.
]]>Journal of Composites Science doi: 10.3390/jcs8030092
Authors: Ashley Blythe Bronwyn Fox Mostafa Nikzad Boris Eisenbart Boon Xian Chai
Sixteen-head automatic tape laying of non-crimped carbon-fibre-reinforced plastic is performed, and the fibre alignment is compared with that produced via hand laying. The effect of fibre alignment is tested via quasi-static and cyclic three-point bending tests. Using the Fill Multilayer (a 16-head tape-laying machine), precision fibre laying of unidirectional fabrics is performed with deliberate misalignment to examine the effect of fibre orientation and investigate the random effect on longitudinal misalignment. The automatic tape-layered coupons are compared with hand-layered carbon fibre tapes to investigate the relationship between the fibre alignment and the flexural strength. A 52% reduction in the fibre alignment scatter is achieved via the Fill Multilayer. Fibre orientation increases lead to a higher flexural strength of 16.08% for Fill Multilayer-made coupons compared with hand-layered samples. An investigation of the correlation between fibre alignment and flexural strength shows that shear-based failure increases exponentially as the alignment decreases. Fill Multilayer-made coupons have a higher void concentration due to ultrasonic welding, but also the highest modulus and flexural strength, as fibre misalignment is reduced to 1.68°, with a modulus degradation of 1.4%.
]]>Journal of Composites Science doi: 10.3390/jcs8030091
Authors: Costas Tsioptsias Konstantinos Leontiadis Xanthi Ntampou Ioannis Tsivintzelis
A large amount of the polypropylene (PP) produced worldwide is used in the form of fibers. In this work, a new modification route for talc and PP is investigated, which is based on the in situ polymerization of a silane–siloxane monomer mixture on the surface of talc particles or PP pellets, respectively. The obtained modified talc and PP samples were used for the development of PP-talc composite drawn fibers. Tensile tests, thermogravimetry (TGA), and X-ray diffraction (XRD) were used for the characterization of the materials. It was observed that such a modification procedure resulted in the exfoliation of some talc particles. Enhanced tensile strength was observed for composite drawn fibers of a low talc content (1% with respect to PP) and a low modifier content (2% with respect to talc), while co-aggregation of talc and silicone may occur at high silicone and talc contents, resulting in the inferior mechanical performance of the corresponding composites. It was concluded that the produced silicone polymer simultaneously acts as a modifier, antioxidant, and compatibilizer. The proposed modification route is promising and should be further optimized.
]]>Journal of Composites Science doi: 10.3390/jcs8030090
Authors: B. R. N. Murthy Amar Murthy Ambekar Anupama Hiremath
In the present work, a metal–matrix composite was casted using the LM13 aluminum alloy, which is most widely used for casting automotive components. Such applications require materials to withstand high operating temperatures and perform reliably without compromising their properties. In this regard, particulate-reinforced composites have gained widespread adaptability. The particulate reinforcements used comprise of one of the widely available industrial by-products. which is fly ash, along with the abundantly available quartz. Hybrid composites are fabricated through the economical liquid route that is widely used in mass production. Though there are numerous published research articles investigating the mechanical properties of metal–matrix composites, very few investigated the thermal properties of the composites. In the present work, thermal properties such as thermal conductivity and thermal diffusivity of cast hybrid composites were evaluated. The particulate reinforcements were added in varied weight percentages to the molten LM13 alloy and were dispersed uniformly using a power-driven stirrer. The melt with the dispersed particulate reinforcements was then poured into a thoroughly dried sand mold, and the melt was allowed to solidify. The quality of the castings was ascertained through density evaluation followed by a microstructural examination. It was found that the composites with only the fly ash particles as a reinforcement were less dense in comparison to the composites cast with the quartz particulate reinforcement. However, the hybrid composite, with both particulate reinforcements were dense. The microstructure revealed a refined grain structure. The thermal diffusivity and thermal conductivity values were lower for the composites cast with only the fly ash reinforcement. On the other hand, the composites cast with only quartz as the particulate reinforcement exhibited higher thermal diffusivity and thermal conductivity. The specific heat capacity was found to be lower for the fly ash-reinforced composites and higher for the quartz-reinforced composites in comparison to the LM13 base matrix alloy. However, the highest value of thermal diffusivity and thermal conductivity were reported for the hybrid composites with a 10 wt.% inclusion of both fly ash and quartz particulate reinforcements.
]]>Journal of Composites Science doi: 10.3390/jcs8030089
Authors: Ananda Hegde Karthik Birur Manjunathaiah Sathyashankara Sharma Gowrishankar Mandya Chennegowda Gajanan Anne Ramakrishna Vikas Sadanand
The current work focuses on the natural aging phenomenon of a eutectoid steel powder-(0.8 wt.%) reinforced Al-Zn-Mg (Al 7075) alloy, which was subjected to a hybrid heat treatment. The hybrid treatment comprises the aging treatment of a matrix and the conventional treatment of a steel reinforcement in a single stretch on the stir cast composite. This material finds uses in space and transportation applications. The hybrid treatment consists of a conventional heat treatment cycle to obtain pearlite, bainite, and martensite phases in steel powder, followed by an age-hardening treatment for the Al 7075 matrix. This hybrid heat treatment resulted in improvements in the hardness and strength over the conventional aging treatment. The peak-aged hybrid specimens were subjected to natural aging in an open atmosphere for a continuous duration of 25 weeks to study the stability of the properties after peak aging. Tests of the mechanical properties such as the hardness and tensile strength along with microstructure analysis were carried out. During natural aging, the hardness of composites decreases irrespective of the quantity of the reinforcement in the composites and the type of reinforcement phase alteration during hybrid heat treatment. Also, the composites subjected to hybrid heat treatment show better resistance to natural aging compared to the conventionally aged samples. Within the group, the hybrid-treated martensite formed into a composite with 6 wt.% reinforcement showed only a 4% reduction in hardness during natural aging, which is an indication of a decent level of resistance to natural aging.
]]>Journal of Composites Science doi: 10.3390/jcs8030088
Authors: Dayanand M. Goudar Julfikar Haider K. Raju Rajashekar V. Kurahatti Deesy G. Pinto
In the present study, the influence of the addition of copper (Cu) on the wear behavior of a Al-12.6Si eutectic alloy developed using the spray forming (SF) method was discussed, and the results were compared with those of as-cast (AC) alloys. The microstructural features of the alloys were examined using both optical and the scanning electron microscopy, and the chemical composition and phase identification were achieved by X-ray diffraction (XRD) analysis. The results revealed that the microstructure of binary the SF alloy consisted of fine primary and eutectic Si phases, evenly distributed in the equiaxed α-Al matrix, whereas the Cu-based SF ternary alloy consisted of uniformly distributed fine eutectic Si particulates and spherical-shaped θ-Al2Cu precipitates, uniformly distributed in α-Al matrix. In contrast, the AC ternary (Al-12.6Si-2Cu) alloy consisted of unevenly dispersed eutectic Si needles and the coarse intermetallic compound θ-Al2Cu in the α-Al matrix. The addition of Cu enhanced the micro hardness of the SF ternary alloy by 8, 34, and 41% compared to that of the SF binary, AC ternary, and binary alloys, respectively. The wear test was conducted using a pin-on-disc wear testing machine at different loads (10–40 N) and sliding velocities (1–3 ms−1). The wear tests revealed that SF alloys exhibited an improved wear behavior in the entire applied load and sliding velocity range in comparison to that of the AC alloys. At a load of 40 N and a sliding velocity of 1 ms−1, the wear rate of the SF2 alloy is 62, 47, and 23% lower than that of the AC1, AC2, and SF1 alloys, respectively. Similarly, at a sliding velocity of 3 ms−1, the wear rate of the SF2 alloy is 52%, 42%, and 21% lower than that of the AC1, AC2, and SF1 alloys, respectively. The low wear rate in the SF2 alloy was due to the microstructural modification during spray forming, the precipitation of fine Al2Cu intermetallic compounds, and increased solid solubility. The SF alloys show an increased transition from oxidative to abrasive wear, while the AC alloys demonstrate wear mechanisms that change from oxidative to abrasive, including delamination, with an increase in sliding velocity and load.
]]>Journal of Composites Science doi: 10.3390/jcs8030087
Authors: Xiaowen Huang Tengsheng Yue Jun Zhang Jinsong Zhang
To improve the long-term performance of concrete engineering in high-altitude areas, waste tire rubber was added to a concrete mix, and freeze–thaw and impact tests were conducted. The effects of waste tire rubber with different particle sizes (10, 20, 30 mesh) and freeze–thaw cycles (0, 25, 50, 75, 100, 125) on the dynamic mechanical properties of concrete materials were studied. The stress–strain curves, peak stress, and fracture morphology of the specimens were analyzed. The microstructure changes of the specimens were also analyzed using scanning electron microscopy (SEM). The results showed the following: (1) Both macroscopic and microscopic analysis results showed that the internal damage of rubber concrete specimens was smaller after freeze–thawing, and the integrity was better after impact, maintaining a loose but not scattered state. The addition of waste tire rubber significantly improved the material’s impact resistance to a certain extent. (2) As the impact pressure increased, the strain rate of the specimens increased linearly, and the dynamic peak stress was linearly positively correlated with the strain rate. (3) After 125 freeze–thaw cycles, the peak stress of the specimens with 30-mesh added rubber decreased significantly less than that of ordinary concrete under 0.3, 0.45, and 0.6 MPa impact pressure. The dynamic peak stress was higher than that of specimens with 10-mesh and 20-mesh added rubber, and the addition of 30-mesh rubber significantly improved the frost resistance and impact resistance of concrete materials. This study can provide new ideas for the engineering application of rubber concrete.
]]>Journal of Composites Science doi: 10.3390/jcs8030086
Authors: Md. Abu Hanif Hyokyeong Shin Danbi Chun Hong Gun Kim Lee Ku Kwac Sang-Won Han Sung-Soo Kang Young Soon Kim
In recent decades, there has been a rise in public consciousness of the adverse effects of expanded skin contact with sunlight, particularly the ultraviolet (UV) spectrum. UV radiation causes serious health problems like skin cancer, early aging, erythema, pigmentation, etc., due to contact with the skin. Therefore, the highly efficient UV-protection materials were manufactured using polypropylene and TiO2 (PPTO) through cost-effective and easy methods. The designated 7.5 PPTO and 15 PPTO were prepared, varying the amount of TiO2, as well as without using TiO2 (PPNF), which was also manufactured as a control material. All the as-synthesized nonwoven fibers were carefully characterized employing a variety of microscopic and spectroscopic methods, such as X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, and contact angle measurements. In conclusion, 15 PPTO showed the highest UV-protection ability (87.5%) compared to 7.5 PPTO and PPNF. In addition, 15 PPTO exhibited 1.76 and 1.32 times higher protection than 7.5 PPTO and PPNF, respectively, when exposed to UB-B radiation. The enhanced activity may be due to the amount of TiO2 because TiO2 increased the product’s absorption and reflection capability. Overall, the PPTO nonwoven fibers can be applied to block harmful UV radiation.
]]>Journal of Composites Science doi: 10.3390/jcs8030085
Authors: Lya Piaia Simone S. Silva Emanuel M. Fernandes Joana M. Gomes Albina R. Franco Isabel B. Leonor Márcio C. Fredel Gean V. Salmoria Dachamir Hotza Rui L. Reis
Osteochondral defects present significant challenges for effective tissue regeneration due to the complex composition of bone and cartilage. To address this challenge, this study presents the fabrication of hierarchical scaffolds combining chitosan/β-tricalcium phosphate (β-TCP) to simulate a bone-like layer, interconnected with a silk fibroin layer to mimic cartilage, thus replicating the cartilage-like layer to mimic the native osteochondral tissue architecture. The scaffolds were produced by freeze-drying and then crosslinking with genipin. They have a crosslinking degree of up to 24%, which promotes a structural rearrangement and improved connection between the different layers. Micro-CT analysis demonstrated that the structures have distinct porosity values on their top layer (up to 84%), interface (up to 65%), and bottom layer (up to 77%) and are dependent on the concentration of β-tricalcium phosphate used. Both layers were confirmed to be clearly defined by the distribution of the components throughout the constructs, showing adequate mechanical properties for biomedical use. The scaffolds exhibited lower weight loss (up to 7%, 15 days) after enzymatic degradation due to the combined effects of genipin crosslinking and β-TCP incorporation. In vitro studies showed that the constructs supported ATDC5 chondrocyte-like cells and MC3T3 osteoblast-like cells in duo culture conditions, providing a suitable environment for cell adhesion and proliferation for up to 14 days. Overall, the physicochemical properties and biological results of the developed chitosan/β-tricalcium phosphate/silk fibroin bilayered scaffolds suggest that they may be potential candidates for osteochondral tissue strategies.
]]>Journal of Composites Science doi: 10.3390/jcs8030084
Authors: Gabriela Loi Pasquale Buonadonna Rayane El Mohtadi Mauro Carta Daniele Lai Mohamad El Mehtedi Francesco Aymerich
The z-pinning reinforcement technique, which involves inserting thin pins through the body of a laminate, has proven highly effective in enhancing the strength of various composite joint configurations. This investigation aims to explore the enhancements achievable through selective z-pinning at very low pin contents on both the static and fatigue performance of composite joints. Single-step joints between carbon/epoxy adherends were reinforced using steel pins arranged in two, three, or four rows of pins parallel to the edges of the overlap, resulting in pin contents ranging from 0.2% to 0.4%. Joint panels were manufactured through co-curing, and coupons were extracted from the panels for static and fatigue tensile testing. The experimental tests show that z-pinning improves the static strength (by about 15%) and extends the fatigue lives of the joints. The ultimate failure of both unpinned and pinned joints is due to the unstable propagation of a crack at the bond line. The superior performances of pinned joints are mainly due to the bridging tractions imposed between the crack faces by z-pins, which delay the growth of the debonding crack. The enhancements in static and fatigue strength achieved by z-pinning were essentially independent of the number of pin rows, and the pins positioned near the joint edges were found to play a dominant role in controlling the structural performance of pinned joints.
]]>Journal of Composites Science doi: 10.3390/jcs8030083
Authors: Konstantinos Tserpes Panagiotis Kormpos
This paper presents a numerical study on the laser shock wave propagation in a 3D woven carbon-fiber-reinforced polymer (CFRP) material by means of detailed and homogenized finite element (FE) models. The aim of this study is to numerically characterize the shock wave response of the 3D woven CFRP in terms of back-face velocity profiles and the induced damage, and to investigate whether the detailed FE models could be effectively replaced by homogenized FE models. The 3D woven geometry was designed using the TexGen 3.13.1 software, while the numerical analyses were executed using the R11.0.0 LS-Dyna explicit FE software. A high-strain-rate behavior was considered for the matrix. The fiber bundles in the detailed models were modeled as a high-fiber-content unidirectional composite laminate, with its mechanical properties calculated by micromechanical equations. A progressive damage material model was applied to both the fiber bundles of the detailed model and the homogenized models. The results of the detailed model reveal a considerable effect of the material’s architecture on the shock wave propagation and sensitivity of the back-face velocity profile to the spot location. Consequently, the homogenized model is not capable of accurately simulating the shock wave response of the 3D woven composite. Moreover, the detailed model predicts matrix cracking in the resin-rich areas and in the bundles with high accuracy, as well as fiber failure. On the contrary, the homogenized model predicts matrix cracking in the same areas and no fiber failure.
]]>Journal of Composites Science doi: 10.3390/jcs8030082
Authors: Abdullah S. Alshammari Alaa Abd Alfatah Muhammad M. Alabdi
Nanocomposite materials have demonstrated excellent performance in many application fields. Metal nanoparticle/graphene oxide composites are among the most promising composite materials for catalytic applications. In this study, nanocomposites of Au-Pd bimetallic particles/graphene oxide were prepared from an aqueous bath and used as catalysts in the oxidation reactions of some chemical compounds. The oxidation and exfoliation of graphite were controlled by varying the acid treatment time. The effects of the treatment time on the properties and performance of the prepared bimetallic-nanoparticle-supported graphene oxide catalysts were very obvious. Depending on the treatment time, a significant improvement in the conversion efficiency ranging from 65% to about 480%, along with a high oxidation selectivity, were achieved. The obtained findings show that the catalytic performance of metal/graphene oxide nanocomposites can be easily maximized by controlling the oxidation and exfoliation of graphene sheets.
]]>Journal of Composites Science doi: 10.3390/jcs8030081
Authors: Ahluwalia Pahaul Michael Johanes Manoj Gupta
A magnesium-based metal matrix composite, Mg-5Se-2Zn-2SiO2, was synthesized using the Disintegrated Melt Deposition (DMD) method followed by hot extrusion. Elemental analysis revealed that the material experienced selenium loss which was attributed to the evaporation of selenium at high temperatures. Superior damping characteristics were exhibited while retaining similar Young’s modulus, and significant grain refinement also resulted in decisively superior mechanical properties such as hardness (32% increase), fracture strain (39% increase), as well as yield and ultimate compressive strength (157% and 54% increase, respectively). These were a consequence of SiO2 addition as well as presence of Mg2Si (and MgSe) intermetallic phases which were detected by X-ray characterization. Furthermore, while the material had lower corrosion resistance than pure magnesium, it retained acceptable corrosion resistance as well as structural integrity after the full immersion duration of 28 days. Overall, the material exhibits promising potential for applications in the biomedical field, especially in development of smaller and lighter implants where mechanical properties are paramount, with key lessons learned for the synthesis of Mg-materials containing selenium for the future.
]]>Journal of Composites Science doi: 10.3390/jcs8030080
Authors: Jia-Ming Zhang Guo-Cui Bao Wen Gao Ri-Qiang Lin Fan Yang Kwok-Ho Lam
Piezoelectric 1-3 composite materials have become extensively utilized in diagnostic ultrasound transducers owing to their high electromechanical coupling coefficient, low acoustic impedance, and low dielectric loss. In this study, Sm-doped PMN-PT ceramic/epoxy 1-3 composite with a ceramic volume fraction of 60% is fabricated by the dice-and-fill method, resulting in a high piezoelectric constant (650 pC/N) and clamped dielectric constant (2350). Utilizing the exceptionally high clamped dielectric constant, a low-frequency (12.4 MHz) ultrasound transducer is developed with a miniature aperture size (0.84 mm × 0.84 mm), exhibiting a −6 dB bandwidth of 70% and an insertion loss of −20.5 dB. The imaging capability of the miniature composite transducer is validated through both phantom and ex vivo imaging. The satisfactory results indicate that Sm-doped ceramic/epoxy composites possess significant potential for miniature devices in biomedical imaging applications.
]]>Journal of Composites Science doi: 10.3390/jcs8030079
Authors: Stefania Skorda Achilleas Bardakas Apostolos Segkos Nikoleta Chouchoumi Emmanouel Hourdakis George Vekinis Christos Tsamis
Additive manufacturing, also known as 3D printing or digital fabrication technology, is emerging as a fast-expanding technology for the fabrication of prototypes and products in a variety of applications. This is mainly due to the advantages of 3D printing including the ease of manufacturing, the use of reduced material quantities minimizing material waste, low-cost mass production as well as energy efficiency. Polylactic acid (PLA) is a natural thermoplastic polyester that is produced from renewable resources and is routinely used to produce 3D-printed structures. One important feature that makes PLA appealing is that its properties can be modulated by the inclusion of nano or microfillers. This is of special importance for 3D-printed triboelectric nanogenerators since it can enhance the performance of the devices. In this work we investigate the influence of SiC micron-sized particles on the mechanical, electrical, and optical properties of a PLA-SiC composite for potential application in triboelectric energy harvesting. Our result show that the ultimate tensile strength of the pure PLA and 1%-doped PLA decreases with the number of fatigue cycles but increases by about 10% when SiC doping increases to 2% and 3%, while the strain at max load was about 3% independent of doping and the effective hardness was increased reaching a plateau at about 2 wt% SiC, about 40% above the value for pure PLA. Our results show that the mechanical properties of PLA can be enhanced by the inclusion of SiC, depending on the concentration of SiC. In addition, the same behavior is observed for the dielectric constant of the composite material increases as the SiC concentration increases, while the optical properties of the resulting composite are strongly dependent on the concentration of SiC.
]]>Journal of Composites Science doi: 10.3390/jcs8020078
Authors: Umanath R. Poojary Sriharsha Hegde
Composite materials are popular substitutes for conventional materials owing to their high strength-to-weight ratio. Reinforcements in the form of woven fabric clothes are common due to their ease of availability and preparation. The use of hybrid intra-ply as reinforcements synergises the advantages of more than one type of fibre. The current work focuses on the preparation of woven carbon fibre (CF) and carbon–Kevlar (CF-K) intra-ply hybrid fibre-based composites. Epoxy resin was used as the matrix and balsa sheet was used as the sandwich material. The angle of orientation of the woven fibre cloth was varied from 0° to 45° along the direction of loading. The dynamic properties of prepared samples were experimentally investigated using an impact hammer test. The natural frequency and damping ratio were influenced by the angle of orientation and the fibre reinforcement. The CF-K hybrid composite showed better dynamic properties when compared with the CF composite. The natural frequency was highest for the 0° sample, it reduced with the angle of orientation, and a reverse trend was observed for damping ratio. Both CF- and CF-K-based composites showed similar trends. The storage modulus variation also showed a similar trend as that of the natural frequency for both types of samples with orientation, but a reverse trend was observed for loss modulus, i.e., the loss modulus increased with the change in the angle of orientation, indicating the improvement in energy storage ability of the composite.
]]>Journal of Composites Science doi: 10.3390/jcs8020077
Authors: Erik Kappel
The Double-Double (DD) laminate family allows for simplification in the context of buckling analysis. Stacking-sequence discussions, known from conventional-laminate optimization, made from 0∘, ±45∘, 90∘ plies, omit for DD. The recently presented DD-specific buckling relation is applied in this article to the 18-panel, ‘horse-shoe’ laminate blending reference case. The use case addresses the challenge of identifying a compatible group of laminates for differently loaded, adjacent regions, as it is a common scenario in wing covers and fuselage skins. The study demonstrates how the novel DD-laminate buckling relation simplifies the process of determining a buckling optimum for a group of laminates. The process of determining the optimum blended DD panel is presented. Its determined mass is compared with minimum masses, presented in earlier studies, which focus on stacking optimization and blending for more conventional ply orientations and laminate stacking conventions.
]]>Journal of Composites Science doi: 10.3390/jcs8020076
Authors: Raffael Bogenfeld
This study explores the experimental characterization of the through-thickness compression properties in unidirectional laminates using cube compression tests. Cubical specimens, each with an edge length of 10 mm, were symmetrically outfitted with biaxial strain gauges and subjected to a compression test. While similar methodologies exist in the literature, this work primarily addresses the potential biases inherent in the testing procedure and their mitigation. The influence of friction-induced non-uniform deformation behavior is compensated through a scaling of the stiffness measurements using finite element (FE) analysis results. This scaling significantly enhances the accuracy of the resulting parameters of the experiments. The ultimate failure of the specimens, originating from stress concentrations at the edges, resulted in fracture angles ranging between 60° and 67°. Such fracture patterns, consistent with findings from other researchers, are attributed to shear stress induced by friction at the load introduction faces. The key findings of this research are the comparisons between the through-thickness modulus (E33c) and strength (X33c) and their in-plane counterparts (E22c and X22c). The results indicate deteriorations of E33c and X33c from E22c and X22c by margins of 5% and 7%, respectively. Furthermore, the results for E22c and X22c were compared with the results obtained through a standard test, revealing a 12% enhancement in strength X22c and 4% underestimated stiffness E22c in the cube compression test.
]]>Journal of Composites Science doi: 10.3390/jcs8020075
Authors: Khouloud Tilouche-Guerdelli Clément Lacoste Didier Perrin Pierre-Jacques Liotier Pierre Ouagne Jacopo Tirillò Fabrizio Sarasini Anne Bergeret
The present study examined the effect of biobased molecules grafted onto wrapped flax rovings on the mechanical properties of fabrics designed for epoxy-based biocomposites, aiming to optimize fiber/matrix adhesion. Biobased solutions, such as tannins from quebracho, were used to treat wrapped flax rovings in comparison to a non-biobased aminosilane solution used as a reference. The chemical treatment is performed using an innovative lab-scale impregnation line. The influence of the solution concentration has been investigated. SEM-EDX and FT-IR confirmed the grafting efficiency of molecules on wrapped rovings. Plain and 5-harness satin fabrics were then manufactured at lab scale with the resulting functionalized rovings. Tensile tests were carried out on rovings and on fabrics. A concentration of 1% silane is sufficient to improve the mechanical properties of rovings and fabrics. The addition of NaOH to tannins strengthens flax fiber rovings more than tannins alone, and the weave pattern influences mechanical performance.
]]>Journal of Composites Science doi: 10.3390/jcs8020074
Authors: Bakhytzhan Lesbayev Nurgali Rakhymzhan Gaukhar Ustayeva Yerkebulan Maral Meiram Atamanov Moldir Auyelkhankyzy Ayazhan Zhamash
This study proposes a method to control the pore-forming process by performing preliminary mechanical activation of the initial rice husk before carbonization. Preliminary mechanical activation of the initial rice husk leads to the loosening of the intercellular substance and its partial depolymerization, thereby increasing the availability of its internal structure for pore formation during carbonization and chemical activation. Using the method described above, nanoporous carbon was obtained with a Brunauer–Emmett–Teller (BET)-calculated specific surface area of 2713 m2/g, a micropore specific surface area calculated by using the Dubinina–Radushkevich (D-R) method of 3099 m2/g, and a total pore volume calculated by using the Barett–Joyner–Halenda (BJH) method of 1.625 cm3/g. Due to these characteristics, the adsorption capacity in the obtained sample was for hydrogen 3.7 wt.% at a temperature of −190 °C and a pressure of 9 kgf/cm2, which is 29.7% higher than the adsorption capacity of nanoporous carbon obtained based on rice husk without mechanical activation. The composite “carbon–platinum” NC-2/Pt10%, at a temperature of 20 °C and a pressure of 9 kgf/cm2, showed an increase in sorption capacity of 27% compared to pure nanoporous carbon NC-2, which is explained by the emergence of the spillover effect.
]]>Journal of Composites Science doi: 10.3390/jcs8020073
Authors: Ljerka Kratofil Krehula Ana Peršić Nina Popov Stjepko Krehula
Due to the intensive search for new types of advanced polymer materials for targeted applications, this work offers insight into the properties of low-density polyethylene/hematite composites. The specific feature of this study lies in the use of elongated hematite particles of different shapes. Uniform ellipsoid-, peanut- and rod-shaped hematite particles were hydrothermally synthesized and incorporated into the polymer matrix of low-density polyethylene (LDPE). LDPE/hematite composites are prepared by melt mixing. Hematite particles are characterized by scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD). The pure LDPE polymer and LDPE/hematite composites were studied by FT-IR and UV-Vis-NIR spectroscopy and by thermogravimetric analysis (TGA). The determination of the mechanical and barrier properties was also carried out. The obtained results indicate the influence of the elongated particles on the improvement of LDPE properties. An increase in thermal stability and UV-absorption was observed as well as the improvement of mechanical and barrier properties. The improvement of the composites’ properties in comparison to the pure LDPE is especially visible in the composites prepared with low content of hematite (0.25%). LDPE/hematite composites have promising characteristics for application as packaging materials with enhanced mechanical, thermal and barrier properties as well as UV-protective materials.
]]>Journal of Composites Science doi: 10.3390/jcs8020072
Authors: Doina Dimonie Ramona Marina Grigorescu Bogdan Trică Celina-Maria Damian Eugeniu Vasile Roxana Trusca Cristian-Andi Nicolae Diana Constantinescu-Aruxandei Florin Oancea
This article compares two exfoliation options of multilayered silicate, one considering the action of shear stress and temperature during melt compounding and another taking into account the action of the thermo-mechanical pretreatment of multilayered silicate in a plasticizer common to the starch and polyvinyl alcohol (PVOH), the two polymers from the compound. Increasing the action time of the shear stress and temperature during melt compounding proved to be an ineffective method for silicate exfoliation following the high degradability of starch and PVOH under thermo-mechanical conditions and the loss of hydration of the multilayered silicate under thermo-mechanical conditions. The obtained results prove that, by pretreating before embedding into the desired starch-PVOH matrix, it was possible to cancel the electrostatic attractions between the component lamellae of a multilayered silicate. During melt compounding with the two polymers, new attractions between the obtained lamellae and the polar groups of each polymer from the blend were settled, and so, without the usage of a liquid plasticizer, exfoliated intercalated nanocomposites were achieved. The improved properties and the practical importance of the new nanocomposites regards the obtaining of a non-degradable material that has a white color, better elastic properties and thermal stability, and a higher dissipation capacity of deformation energy.
]]>Journal of Composites Science doi: 10.3390/jcs8020071
Authors: Ruiqi Zheng Jianyong Pang Jian Sun Yongqiang Su Guoping Xu
In order to enhance the practical application of carbon-fiber-reinforced concrete (CFRC) in engineering, it is necessary to study the damage mechanism of CFRC. Experimental research on the mechanical properties of CFRC under multiple strain rates was conducted. Five different fiber contents were analyzed to study the compressive strength and tensile strength of CFRC, and the damage characteristics of CFRC under multiple strain rates were analyzed based on failure modes and energy changes. An energy-based damage constitutive model was established. The results showed the following: (1) When the carbon fiber content was 0.4%, CFRC had the best comprehensive performance, with a 15.02% increase in compressive strength and a 51.12% increase in tensile strength. With the increase in strain rate, the compressive strength of the concrete increased. (2) Under high strain rates, carbon fiber significantly enhanced the compressive strength of the concrete, and the input energy, elastic strain energy, and dissipated energy increased. The peak value of the elastic strain energy conversion rate increased, and the minimum value of the dissipated energy conversion rate decreased. (3) Under the same strain rate, the CFRC had a larger inflection point of dissipated energy corresponding to the strain compared to the reference group of concrete during the loading process. A constitutive model for CFRC was established based on damage mechanics and probability statistics. The research results will provide theoretical references for the application of carbon-fiber-reinforced concrete.
]]>Journal of Composites Science doi: 10.3390/jcs8020070
Authors: Sergey V. Yudintsev Michael I. Ojovan Victor I. Malkovsky
The current policy of managing high-level waste (HLW) derived in the closed nuclear fuel cycle consists in their vitrification into B-Si or Al-P vitreous forms. These compounds have rather limited capacity with respect to the HLW (5–20 wt%), and their properties change over time due to devitrification of the glasses. Cardinal improvement in the management of HLW can be achieved by their separation onto groups of elements with similar properties, followed by their immobilization in robust waste forms (matrices) and emplacement in deep disposal facilities. One of the possible fractions contains trivalent rare-earth elements (REEs) and minor actinides (MAs = Am and Cm). REEs are the fission products of actinides, which are mainly represented by stable isotopes of elements from La to Gd as well as Y. This group also contains small amounts of short-lived radionuclides with half-lives (T1/2) from 284 days (144Ce) to 90 years (151Sm), including 147Pm (T1/2 = 2.6 years), 154Eu (T1/2 = 8.8 years), and 155Eu (T1/2 = 5 years). However, the main long-term environmental hazard of the REE–MA fraction is associated with Am and Cm, with half-lives from 18 years (244Cm) to 8500 years (245Cm), and their daughter products: 237Np (T1/2 = 2.14 × 106 years), 239Pu (T1/2 = 2.41 × 104 years), 240Pu (T1/2 = 6537 years), and 242Pu (T1/2 = 3.76 × 105 years), which should be immobilized into a durable waste form that prevents their release into the environment. Due to the heat generated by decaying radionuclides, the temperature of matrices with an REE–MA fraction will be increased by hundreds of centigrade above ambient. This process can be utilized by selecting a vitreous waste form that will crystallize to form durable crystalline phases with long-lived radionuclides. We estimated the thermal effects in a potential REE–MA glass composite material based on the size of the block, the content of waste, the time of storage before immobilization and after disposal, and showed that it is possible to select the waste loading, size of blocks, and storage time so that the temperature of the matrix during the first decades will reach 500–700 °C, which corresponds to the optimal range of glass crystallization. As a result, a glass–ceramic composite will be produced that contains monazite ((REE,MA)PO4) in phosphate glasses; britholite (Cax(REE,MA)10-x(SiO4)6O2) or zirconolite ((Ca,REE,MA)(Zr,REE,MA)(Ti,Al,Fe)2O7), in silicate systems. This possibility is confirmed by experimental data on the crystallization of glasses with REEs and actinides (Pu, Am). The prospect for the disposal of glasses with the REE–MA fraction in deep boreholes is briefly considered.
]]>Journal of Composites Science doi: 10.3390/jcs8020069
Authors: Mohammad Ali Golshokouh Nima Refahati Pouyan Roodgar Saffari
The effect of silicon nanoparticles with different percentages (2, 5, 7, and 10 wt.%) on moisture absorption in environments with different pHs (5, 6, 7, 8, 9) as well as fracture toughness of polymethyl methacrylate is discussed. The samples were prepared using pressure molding. Fracture strength was tested via the three-point bending method according to the ASTM D5045 standard and moisture absorption rate according to the absorption test according to the ASTM D570 standard. SEM images show that up to 7%, the dispersion of silica nanoparticles is acceptable, but the homogeneity is not acceptable at 10%. The results indicate that the increase in silica nanoparticles has improved the fracture toughness of the manufactured parts. The highest fracture toughness improvement is about 57% in the optimal state at 5%. Also, increasing silica nanoparticles increased the moisture absorption in the produced samples. In addition, as the acidic or base of the liquid moves to neutral, the reaction between the base polymer molecules and the test liquid decreases and, so, the moisture absorption also increases.
]]>Journal of Composites Science doi: 10.3390/jcs8020068
Authors: Hind M. Saleh Salim Albukhaty Ghassan M. Sulaiman Mosleh M. Abomughaid
The effective removal of organic dyes from aqueous solutions is of paramount importance in addressing environmental pollution challenges. Methylene blue (MB), a prevalent cationic dye in various industries, has raised concerns due to its persistence and potential adverse effects on ecosystems. This study explores the design, preparation, and characterization of Polycaprolactone–Chitosan (PCL–CH) nanofibers via electrospinning for the removal of MB. PCL, known for its biodegradability and mechanical properties, serves as the primary matrix, while chitosan (CH), with its biocompatibility and amino functionalities, offers enhanced adsorption potential. The electrospinning process yields nanofibers with tailored compositions and controlled morphology. The synthesized nanofibers are systematically characterized, encompassing structural analysis by Fourier transform infrared (FT–IR), spectroscopy, morphology, and composition assessment via Field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS), zeta potential, as well as rheological behavior evaluation. The adsorption uptake of MB onto these nanofibers is investigated, considering the influence of solution pH and initial dye concentration. The results reveal significant enhancements in adsorption capacity, especially with the incorporation of CH, with the PCL–CH 30% nanofibers exhibiting outstanding performance. The pH-dependent behavior underscores the importance of environmental factors in the adsorption process, while higher dye concentrations provide a stronger driving force for adsorption. These findings position PCL–CH nanofibers as promising adsorbents for the efficient removal of MB and potentially other organic contaminants from aqueous solutions. The study contributes to the development of sustainable materials for environmental remediation, wastewater treatment, and related applications, aligning with ongoing efforts to address water pollution challenges.
]]>Journal of Composites Science doi: 10.3390/jcs8020067
Authors: Victor Hugo M. Almeida Raildo M. Jesus Gregório M. Santana Thaís B. Pereira
The escalating global demand for polymer products and the consequent disposal challenge necessitate technological and sustainable solutions. Recent advances in the development of materials used in 3D printing equipment are described in this review, with a focus on new biocomposite materials. The investigation delves into biocomposites comprising PLA and its blends with other polymers, reinforced by plant fibers, with a particular focus on research conducted over the last five years. The information related to the raw materials’ physical, chemical, and processing properties necessary for creating biocomposite filament and printed parts were summarized. The best results in terms of tensile and flexural strength were presented and discussed, signposting future research avenues and desirable objectives. The findings elucidate that the inclusion of plant fibers led to a reduction in mechanical strength relative to pure PLA; however, when smaller particle sizes of plant fibers were added in volumes below 10%, it resulted in improved performance. Moreover, physical and/or chemical pretreatment of fibers, along with the isolation of cellulose fibrils, emerged as pivotal strategies for bolstering mechanical strengths. Noteworthy are the promising prospects presented by the incorporation of additives, while the refinement of printing parameters is key to improving the tensile and flexural strength of printed components.
]]>Journal of Composites Science doi: 10.3390/jcs8020066
Authors: Puneethraj Hebbalu Puttaswamygowda Sathyashankara Sharma Achutha Kini Ullal Manjunath Shettar
This study explores the synergistic effects of incorporating coir fibers and nanoclay into epoxy resin composites. Coir, a renewable and cost-effective natural fiber, undergoes an alkaline treatment to influence its ability to form strong interfacial bonding with the epoxy matrix. To further enhance the mechanical properties of the composite, montmorillonite nanoclay, surface-modified with aminopropyltriethoxysilane and octadecyl amine, is introduced. The research investigates different combinations of coir fiber content (20, 30, and 40 wt%) and nanoclay loading (0, 2, and 4 wt%) with epoxy resin. The composites are fabricated through an open molding process, and the mechanical properties are evaluated using tensile and flexural tests according to the ASTM D638 and D7264 standards, respectively. The tensile and flexural strengths of the 40 wt% coir fiber-reinforced epoxy composite are found to be 77.99 MPa and 136.13 MPa, which are 44% and 23% greater than pure epoxy, respectively. Furthermore, the strengths displayed a 23% improvement in tensile strength with 4 wt% and a 31.4% improvement in flexural strength with 2 wt% nanoclay as additional reinforcement. Scanning electron microscopy is employed for fractographic analysis of the fractured specimens from the tensile test. The study underscores the importance of understanding the interplay between natural fibers, nanoclay, and epoxy resin for optimizing the composite’s performance in real-world applications.
]]>Journal of Composites Science doi: 10.3390/jcs8020065
Authors: Philipp K. W. Picard Tim A. Osswald Swen Zaremba Klaus Drechsler
This study explores cost-effective and customized composite applications by strategically placing carbon fiber-reinforced thermoplastics in multi-material designs. The focus is on developing a model for the simultaneous processing of non-reinforced and reinforced thermoplastic layers, with the aim of identifying essential parameters to minimize insert flow and ensure desired fiber orientation and positional integrity. The analysis involves an analytical solution for two layered power-law fluids in a squeeze flow setup, aiming to model the combined flow behavior of Newtonian and pseudo-plastic fluids, highlighting the impact of the non-Newtonian nature. The behavior reveals a non-linear trend in the radial flow ratio towards the logarithmic consistency index ratio compared to a linear trend for Newtonian fluids. While a plateau regime of consistency index ratios presents challenges in flow reduction for both layers, exceeding this ratio, depending on the height ratio of the layers, enables a viable overmolding process. Therefore, attention is required when selectively placing tailored composites with long-fiber-reinforced thermoplastics or unidirectional reinforcements to avoid operating in the plateau region, which can be managed through appropriate cavity or tool designs.
]]>Journal of Composites Science doi: 10.3390/jcs8020064
Authors: Haotian Hu Zhenmeng Xia Qiang Tao Zixin Ye Kaifeng Yuan Leying Song
Origami-based membrane structures have shown great potential to revolutionize the construction of deployable and lightweight space structures in the future. However, the efficient unfolding mechanism puts forward major challenges to the practical realization of space-deployable structures. Here, a smart grid-reinforced membrane origami (SGRMO) is presented. The unfolding action hinges upon the application of forces facilitated by shape memory polymer composites (SMPCs). Subsequent locking action ensues through the restoration of the initial rigidity, accomplished via cooling mechanisms. This novel structure achieves the required lightweight and functionality by employing the grid design concept and effectively reduces the decline in unfolding extent caused by irreversible plastic deformation at the crease. Its recovery properties, including unfolding angle, distance, and surface precision, are experimentally and analytically investigated under different conditions. The results indicate that the structure can be reliably unfolded into the predefined shapes. In the case of Miura-SGRMO, the optimal surface precision is attained when the angle-ψ registers at 30°. The results of this study are expected to serve as the design of ultra-large flexible solar arrays and deployable antenna structures.
]]>Journal of Composites Science doi: 10.3390/jcs8020063
Authors: Jiaoqing Li Li Li Yongxuan Liu Jin Liu Lin Li
Manganese oxides reportedly exhibit pronounced adsorption capacities for numerous heavy-metal ions owing to their unique structural properties. Herein, a biogenic manganese oxide (BMO) composite was developed and used to remove Ni ions from Ni2+-containing electroplating wastewater. The formation of BMO and the micro-/nanoscale fine microstructure were characterized via scanning/high-resolution transmission electron microscopies and X-ray diffraction assays. Under the optimized conditions, with an adsorption temperature of 50 °C, pH 6, the BMO composite showed a 100% removal efficiency within a rapid equilibrium reaction time of 20 min towards an initial Ni2+ concentration of 10 mg L−1 and a remarkable removal capacity of 416.2 mg g−1 towards an initial Ni2+ concentration of 600 mg L−1 in Ni-electroplating wastewater. The pseudo-second-order equation was applicable to sorption data at low initial Ni2+ concentrations of 10–50 mg L−1 over the time course. Moreover, Freundlich isotherm models fitted the biosorption equilibrium data well. Fourier-transform infrared spectroscopic analysis validated that the removal capacity of the BMO composite was closely associated with structural groups. In five continuous cycles of adsorption/desorption, the BMO composite exhibited high Ni2+ removal and recovery capacities, thereby showing an efficient and continuous performance potential in treating Ni2+-containing industrial wastewater.
]]>Journal of Composites Science doi: 10.3390/jcs8020062
Authors: Mohammad younes Almarahfeh Hassan K. Juwhari Ziad M. Elimat Ziad M. Alqudah
The goal of this paper is to study the effects of gamma irradiation and samples’ aging on the AC-electrical properties of hybrid epoxy resin as a function of frequency, temperature, and (zinc oxide) ZnO content (0, 0.049, 0.099, 0.149, and 0.199 wt) at 0.001 wt of conductive (carbon black) CB nanoparticles. The irradiation processes were administered at room temperature in a gamma chamber utilizing a Cobalt 60 source of average energy = 1.25 MeV with doses = 100, 750, and 1000 Gy. The AC-electrical properties, including the impedance, dielectric constant, dielectric loss, conductivity, and activation energy of the nanocomposites, were initially studied after years of sample preparations. The collected empirical data were later analyzed before and after the gamma irradiation. The results showed that exposing samples to different doses of gamma radiation affects these AC-electrical properties significantly. It was found that the energy gap decreased as the dosage of gamma radiation increased. This could be explained as the gamma-irradiation processes induce changes in the structure of the epoxy hybrid nanocomposites by reinforcing the metal–polymer bonding and hence, causing the release of more free electrons inside the hybrid nanocomposites. Moreover, the sample aging results showed that the AC-electrical conductivity decreased with time for all samples. Hence, this study demonstrated why the γ-irradiation technique can be considered a powerful way to treat, recover, and/or enhance the electrical features of the tested epoxy hybrid nanocomposites.
]]>Journal of Composites Science doi: 10.3390/jcs8020061
Authors: Christoph Burgstaller Károly Renner
Wood–plastic composites (WPC) are partially biobased composite materials that exhibit appealing properties, but also some drawbacks. One is the inherent propensity to take up water, which influences different composite properties. In this work, we investigated the general water uptake behavior of injection-molded WPC and applied a simple model to evaluate different formulations. We found that the major influence is the wood content, but also, wood particle size showed a distinct influence on the water uptake speed, while the saturation concentration correlated with the equilibrium moisture content of the wood. The mechanical properties, such as elastic modulus and tensile strength, were reduced with increasing water uptake, and the reduction correlated with wood content and the moisture content of the wood, while the particle size did not show an influence in the investigated region.
]]>Journal of Composites Science doi: 10.3390/jcs8020060
Authors: Nedson T. Kashaija Viktória Gável Krett Gergely Kovago Akos Miklós Kürthy Csaba Szabó Erika Tóth Zsuzsanna Szabó-Krausz
Wastewater treatment plants (WWTPs) are critical infrastructures for wastewater management, and their durability is crucial. Due to their excellent water tightness and strength, cementitious materials are used to build WWTPs. However, the performance of these materials is affected by aggressive environments. There are few in situ experiments in the literature regarding the deterioration of cementitious materials in WWTPs. This paper investigates their deterioration mechanisms in a sewage pumping station and a sand-trap structure of a WWTP. In situ experiment was conducted by exposing cement specimens in both locations for 1, 2, 3 and 7 months. The physical and morphological changes of the specimens were examined using stereo microscopy and scanning electron microscopy, whereas the mineralogical/solid phase changes were examined using X-ray diffraction. The results showed that the specimens from the pumping station formed colored surface products, which were confirmed to be secondary minerals (i.e., gypsum and ettringite), whereas there were no colored surface products in the sand-trap structure. The results demonstrated that cementitious materials subjected to wastewater vapors (in a pumping station) had higher deterioration effects than those subjected to wastewater liquid (in a sand-trap structure), suggesting that the wastewater vapors are more aggressive toward cementitious materials than wastewater liquids.
]]>Journal of Composites Science doi: 10.3390/jcs8020059
Authors: Safaa Saleh Ahmed Salama Ola M. Awad Roberto De Santis Vincenzo Guarino Emad Tolba
In this work, novel multifunctional electrospun nanofibrous membranes made of polyamide (PA6) and loaded with silica (SiO2) and/or titanium dioxide (TiO2) nanoparticles were fabricated. SiO2 NPs were first prepared and then characterized by TEM, FE-SEM, and FTIR, and by using XRD techniques, confirming the formation of cristobalite tetragonal crystals with high purity. Different nanofibrous mats, loaded with SiO2 NPs, TiO2 NPs, or both SiO2 and TiO2 NPs, were investigated. Morphological studies indicated that SiO2 and TiO2 nanoparticles tend to be arranged along the fiber surface, also promoting the formation of anatase nanorods when they are mixed into the nanofibers. In this last scenario, mechanical tests have demonstrated that the presence of SiO2 contributed to balancing the mechanical response of fibers that are negatively affected by the presence of TiO2 NPs—as confirmed by tensile tests. More interestingly, the presence of SiO2 did not negatively affect the antibacterial response against different bacteria populations (i.e., Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Bacillus subtilis, and Candida albicans), which is mainly ascribable to the presence of TiO2 particles. Accordingly, the TiO2- and TiO2/SiO2-loaded fibers showed higher methylene blue (MB) absorption values—i.e., 26 mg/g and 27 mg/g—respectively, compared to the SiO2-loaded fibers (23 mg/g), with kinetics in good agreement with the second-order kinetic model. The obtained findings pave the way for the formation of novel antibacterial membranes with a promising use in water purification.
]]>Journal of Composites Science doi: 10.3390/jcs8020058
Authors: Tamer M. Hamdy Ali Abdelnabi Maha S. Othman Rania E. Bayoumi
The surface characteristics of the restorative material are essential to its longevity. Since resin composites are polymeric-based materials, they could be degraded when exposed to oral conditions and chemical treatment. Certain chemical solutions, such as fluoride varnish, have the potential to deteriorate the resin composite’s surface properties such as gloss and hardness. The current study aimed to assess and compare the surface gloss and hardness of different types of dental resin composites (nanohybrid, ormocer, bulk-fill flowable direct composites, and indirect CAD/CAM resin composite blocks (BreCAM.HIPC)) after a single application of Bifluorid 10 varnish. A total of 80 disc-shaped resin composite specimens were evenly distributed in four groups of 20 specimens. These were divided into two equal subgroups of specimens with topical fluoride (TF) application (n = 10) and without TF application (n = 10). The specimens were examined for surface gloss and hardness. Independent sample t-test was used to investigate statistically the effect of TF on the gloss as well as the hardness of each material. One-way ANOVA and post hoc tests were used to assess the difference in gloss and hardness among the materials without and with TF application. The significance level was adjusted to p ≤ 0.05. The results of gloss showed that the TF application led to a significant reduction in gloss values of all tested composites. The gloss among the various materials was significantly different. The TF had no significant effect on the hardness of nanohybrid, bulk-fill flowable, and BreCAM.HIPC composites (p = 0.8, 0.6, and 0.3, respectively). On the other hand, the hardness of ormocer was significantly reduced after TF application. Comparing the different resin composite materials, the hardness significantly differed. This study concluded that surface gloss and hardness seem to be impacted by the type and composition of the resin composites and vary depending on fluoride application.
]]>Journal of Composites Science doi: 10.3390/jcs8020057
Authors: Liudmila N. Stepanova Roman M. Mironenko Mikhail V. Trenikhin Aleksandra N. Serkova Aleksei N. Salanov Aleksandr V. Lavrenov
Catalysts based on CoCuMgAl mixed oxides were synthesized and studied in the hydrogenations of furfural and 5-hydroxymethylfurfural under different conditions. The changes in the structural properties of the catalysts at different stages of their preparation were studied using a set of physical methods (XRD, SEM, and TEM). It was shown that the fine regulation of the chemical compositions of the mixed oxides (i.e., changes in the Co/Cu ratio) made it possible to vary the structure, morphology, and catalytic properties of the samples. The phase composition of catalysts with Co/Cu = 1 did not change during the catalytic reaction, although the initial catalysts had a less-homogeneous morphology. 5-hydroxymethylfurfural conversion was higher for the samples with Co/Cu = 1. Furfural conversion increased when raising the Co/Cu ratio. The selectivity toward furfuryl alcohol for the catalyst with Co/Cu = 2 under mild conditions of furfural hydrogenation was more than 99%. The results obtained are important for the development of the scientific foundations of the preparation of hydrogenation catalysts with a fine-tunable composition in order to obtain the desired hydrogenation products.
]]>Journal of Composites Science doi: 10.3390/jcs8020056
Authors: Kazuto Tanaka Masaki Taniguchi
In the press and injection hybrid molded parts of fiber-reinforced thermoplastics (FRTPs), failure at the interface between the surface material (the outer shell) and the ribs (the injection part) or that at the injection part has become an issue. Adding a resin layer to the rib roots at the same time that the ribs are molded through injection has been proposed, which may increase the mechanical properties and reduce the material cost. To prevent failure at the injection part, the use of fiber-reinforced resin as an injection material has been suggested. This approach contributes to a higher bond strength by lowering the molding shrinkage rate. In this study, the hat-shaped parts of carbon fiber-reinforced thermoplastics (CFRTPs) with fiber-reinforced and neat resin layers at the rib root were fabricated through press and injection hybrid molding, and their mechanical properties were evaluated through three-point bending tests. The effects of the resin layer at the rib root and the existence or nonexistence of fiber reinforcement on the mechanical properties, as well as the relationship between the material cost and the mechanical properties, were clarified through an experiment and FEM analysis. The bond strength was also evaluated through tensile tests that were undertaken at the rib root. Molded parts with neat PA6 and glass fiber-reinforced PA6 resin layers at the rib roots showed higher bond strength than those without resin layers. In a three-point bending test of a CFRTP hat-shaped part with a resin layer at the rib roots, the use of a 1 mm thick CFRTP laminate for the outer shell and glass fiber-reinforced PA6 resin as the injection material showed the same stiffness as a part that used a 2 mm thick CFRTP laminate for the outer shell. FEM analysis showed that the resin layer prevented the concentration of strain at the rib roots, and the model that used a 1 mm thick CFRTP laminate for the outer shell and glass fiber-reinforced PA6 resin as the injection material showed the best specific stiffness in this study. By adding a resin layer to the rib roots, the fabrication of molded parts with excellent specific stiffness was enabled at a small increase in cost.
]]>Journal of Composites Science doi: 10.3390/jcs8020055
Authors: Mariana P. Salgueiro Fábio A. M. Pereira Carlos L. Faria Eduardo B. Pereira João A. P. P. Almeida Teresa D. Campos Chaari Fakher Andrea Zille Quyền Nguyễn Nuno Dourado
In additive manufacturing (AM), one of the most popular procedures is material extrusion (MEX). The materials and manufacturing parameters used in this process have a significant impact on a printed product’s quality. The purpose of this work is to investigate the effects of infill percentage and filament orientation on the mechanical properties of printed structures. For this reason, the characterisation of polylactic acid (PLA) was done numerically using the finite element method and experimentally through mechanical tests. The experiments involved three-point bending and tensile tests. The results showed that mechanical performance is highly dependent on these processing parameters mainly when the infill percentage is less than 100%. The highest elastic modulus was exhibited for structures with filament align at 0° and 100% infill, while the lowest one was verified for specimen filament aligned at 0° and 30% infill. The results demonstrated that the process parameters have a significant impact on mechanical performance, particularly when the infill percentage is less than 100%. Structures with filament aligned at 0° and 100% infill showed the maximum elastic modulus, whereas specimens with filament oriented at 0° and 30% infill showed the lowest. The obtained numerical agreement indicated that an inverse method based only on the load–displacement curve can yield an accurate value for this material’s elastic modulus.
]]>Journal of Composites Science doi: 10.3390/jcs8020054
Authors: Lusine Elbakyan Irina Zaporotskova David Hayrapetyan
The physical chemistry of surface phenomena in polymers is an important issue when studying the interaction of polymers with solid surfaces. This is due to the fact that most of the modern polymer materials are heterogeneous systems with highly developed phase separation surfaces. An example of such materials can be reinforced plastic, filled thermoplastics, reinforced rubber, paint coatings, etc. Polymer adsorption at the boundary of the phase separation process in solids plays an important role in the reinforcing effect of fillers, adhesion, gluing and obtaining composite materials with high strength properties. Compositions based on polyvinyl alcohol (PVA) modified with carbon nanotubes (CNTs) can be used as an interesting and informative system for studying the structure and properties of polymer nanocomposites, especially in a highly oriented state. PVA has one of the simplest chemical structure among the polymers, containing a functional (hydroxyl) group capable of participating in interphase interactions. In turn, carbon nanotubes with unique strength properties are currently products of industrial production, which makes it possible to control and modify their properties. To prove the possibility of creating new composite materials with improved strength characteristics, the mechanisms of interaction between PVA and CNTs are studied by modeling the adsorption processes of a polymer fragment on the outer surface of single-layer carbon nanotubes of different chirality, performed within the framework of the modern DFT calculation method. The main adsorption characteristics of the process and the features of the electron energy structure of the resulting composite systems are determined.
]]>Journal of Composites Science doi: 10.3390/jcs8020053
Authors: Melkie Getnet Tadesse Abdella Simegnaw Ahmmed Jörn Felix Lübben
The rising demand for energy storage systems with high power density, rapid charge/discharge capabilities, and long cycle life has pushed extensive research into advanced materials for supercapacitor applications. There are several materials under investigation, and among these materials, conductive polymer composites have emerged as promising candidates due to their unique combination of electrical conductivity, flexibility, and facile synthesis. This review provides a comprehensive analysis of recent advancements in the development and application of conductive polymer composites for supercapacitor applications. The review begins with an overview of the fundamental principles governing electrical conductivity mechanism, applications of conductive polymers and the specific requirements for materials employed for these devices. Subsequently, it delves into the properties of conductive polymers and the challenges associated with their implementation for supercapacitors, highlighting the limitations of pristine conductive polymers and the strategies employed to overcome these drawbacks through composite formation. In this review, conductive polymer composites and their applications on supercapacitors are explored, and their advantages and disadvantages are discussed. Finally, the electromechanical properties of each conductive polymer composite are elaborated.
]]>Journal of Composites Science doi: 10.3390/jcs8020052
Authors: Jacques Lamon
The present paper investigates the unexpected unstable failure observed commonly on fiber tows tensile-tested under strain-controlled loading, although the force on the fibers should theoretically be relaxed under controlled strain. A model of the reaction of the load train when the fibers break under strain-controlled conditions is proposed. The criterion for instability is based on the comparison of the filament strength gradient and the overstress induced by the reaction of the load train when the fibers fail. The contribution of multiplet filament failures attributed to the fiber inter-friction and stress waves was taken into account. The compliance of the load train for the test results considered in the present paper was measured. It is shown that, depending on the number of filaments sharing the overload, the values of the structural parameters, and the fiber characteristics, the condition of unstable failure may have been fulfilled by the SiC fiber tows that were tested in house, as discussed in the present paper. The critical parameters that were identified and quantified include the load train compliance, gauge length, fiber stiffness, and bonding of the tow ends. This should allow the proper conditions for stable failure. Important implications for the validity and an analysis of the strengths derived from the unstable fracture of the tows are discussed.
]]>Journal of Composites Science doi: 10.3390/jcs8020051
Authors: Michael MacDonald Igor Zhitomirsky
This investigation addresses increasing interest in advanced composite materials, combining capacitive properties and spontaneous magnetization for energy storage applications in supercapacitors. The capacitive properties of ferrimagnetic NiFe2O4 (NFO) spinel nanoparticles with magnetization of 30 emu g−1 were enhanced using high-energy ball-milling and the use of advanced dispersant, which facilitated charge transfer. NFO electrodes with an active mass of 40 mg cm−2 showed a capacitance of 1.46 F cm−2 in 0.5 M Na2SO4 electrolyte in a negative potential range. The charging mechanism in the negative potential range in Na2SO4 electrolyte was proposed. NFO was combined with conductive polypyrrole polymer for the fabrication of composites. The analysis of the capacitive behavior of the composites using cyclic voltammetry, chronopotentiometry and impedance spectroscopy at different electrode potentials revealed synergy of contributions of NFO and PPy. The highest capacitance of 6.64 F cm−2 was obtained from cyclic voltammetry data. The capacitance, impedance, and magnetic properties can be varied by variation of electrode composition. Composite electrodes are promising for application in anodes of asymmetric magnetic supercapacitors for energy storage and magnetically enhanced capacitive water purification devices.
]]>Journal of Composites Science doi: 10.3390/jcs8020050
Authors: Qianjiang Wu Farid Taheri
The first paper of this two-part series discussed the development of a novel lightweight 3D wood dowel-reinforced glass epoxy hybrid composite material (3DdrFRP) and its manufacturing procedures. It also experimentally compared the performance of scaled utility poles made from conventional 2D E-glass epoxy and 3DdrFRP materials. In the second part, the development of robust, efficient, and fairly accurate nonlinear finite element (FE) models is outlined. The models are calibrated based on experimental results and used to simulate the performance of equivalent 2D and 3D poles, proving the integrity of the numerical models. Additionally, a simplified analytical calculation method is developed for practicing engineers to evaluate the stiffness of 3D-DrFRP poles fairly accurately and quickly.
]]>Journal of Composites Science doi: 10.3390/jcs8020049
Authors: Pooyan Parnian Alberto D’Amore
This paper presents a study of the electrical and mechanical properties of polystyrene (PS)/carbon nanotube (CNT) composites prepared using the doctor blade technique. The nanocomposite films of PS/CNT were prepared by casting a composite solution of PS/CNT in tetrahydrofuran (THF) on a glass substrate using a doctor blade and drying in an oven. The nanocomposite films were then characterized using a tensile test and the four-point probe method to evaluate their mechanical properties and electrical conductivity. The experimental results were used to analyze the unpredicted behavior of the nanocomposite films. The experimental results showed that the electrical conductivity of the nanocomposite films became almost insensitive or unmeasurable with increasing CNT content for very dilute PS–THF solutions. In contrast, at higher PS concentrations, film conductivity increased to a given CNT threshold and then decreased. Based on PS–THF viscosity–concentration data, a discussion is elaborated that partially justifies the experimental results.
]]>Journal of Composites Science doi: 10.3390/jcs8020048
Authors: Anna Zimina Aleksey Nikitin Vladislav Lvov Inna Bulygina Polina Kovaleva Stepan Vodopyanov Mikhail Zadorozhnyy Elizaveta Peshkina Saida Karshieva Rajan Choudhary Maxim Abakumov Fedor Senatov
The acceleration in advancements of smart materials and non-contact controlled devices in the field of 4D printing is facilitated by the use of magnetically responsive shape memory polymer (SMP) composites. This study is dedicated to the development of promising shape memory materials based on polylactic acid (PLA) and cobalt ferrite (CoFe2O4) nanoparticles. The activation of the shape memory effect (SME) in magnetic nanoparticle composites was achieved by applying a high-frequency alternating magnetic field (HFAMF). The PLA/CoFe2O4 composites exhibited a remarkable shape recovery ratio (>84%) and underwent rapid heating when exposed to HFAMF. The interaction of these composites with mouse adipose-derived mesenchymal stem cells demonstrated adequate cytocompatibility. The rapid magnetosensitive behavior and high shape recovery characteristics of PLA/CoFe2O4 composites make them promising candidates for biomedical applications.
]]>Journal of Composites Science doi: 10.3390/jcs8020047
Authors: Mir Waqas Alam Nassiba Allag Maisari Utami Mir Waheed-Ur-Rehman Mohd Al Saleh Al-Othoum Shima Sadaf
The nanocrystalline bismuth oxide (Bi2O3) was produced utilizing a green combustion process with Mexican Mint gel as the fuel. The powder X-ray diffraction (PXRD) method proved the nanocrystalline nature and Bi2O3 nanoparticles (BONPs) in α phase and the average crystalline size of BONPs nanoparticles has been found to be 60 nm. The spherical-shaped structure with bright dot-like spots in the center of the selected area diffraction (SAED) is confirmed by the scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDAX) in conjunction with the transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) demonstrating the crystalline behavior of green NPs. The Kubelka-Monk function was used to analyze diffuse reflectance spectra, and the results revealed that BONPs have a band gap of 3.07 eV. When utilized to evaluate the photocatalytic capabilities of NPs, the direct green (DG) and fast orange red (F-OR) dyes were found to be activated at 618 and 503 nm, respectively. After 120 min of exposure to UV radiation, the DG and F-OR dyes’ photodegradation rate reduced its hue by up to 88.2% and 94%, respectively. Cyclic voltammetry (CV) and electrochemical impedance techniques in 0.1 N HCl were used to efficiently analyze the electrochemical behavior of the produced BONPs. A carbon paste electrode that had been enhanced with BONPs was used to detect the glucose and uric acid in a 0.1 N HCl solution. The results of the cyclic voltammetry point to the excellent electrochemical qualities of BONPs. Bi2O3 electrode material was found to have a proton diffusion coefficient of 1.039 × 10−5 cm2s−1. BONP exhibits significant potential as an electrode material for sensing chemicals like glucose and uric acid, according to the electrochemical behavior.
]]>Journal of Composites Science doi: 10.3390/jcs8020046
Authors: Ying Yang Pingfei Wang Guiju Zhang Shan He Baocai Xu
Wound management heavily relies on the vital contribution of wound dressings, emphasizing the significance of finding an ideal dressing that can fulfill the intricate requirements of the wound healing process with multiple functions. A promising strategy is combining several materials and therapies to create multifunctional wound dressings. Nanocomposite hydrogel dressings based on nanomaterials, combining the advantages of nanomaterials and hydrogels in wound treatment, can significantly improve their respective performance and compensate for their shortcomings. A variety of nanocomposite wound dressings with diverse structures and synergistic functions have been developed in recent years, achieving ideal results in wound management applications. In this review, the multiple functions, advantages, and limitations of hydrogels as wound dressings are first discussed. Additionally, the application of inorganic nanomaterials in wound healing is also elaborated on. Furthermore, we focused on summarizing and analyzing nanocomposite hydrogel dressings for wound healing, which contain various inorganic nanomaterials, including metals, metal oxides, metal sulfides, carbon-based nanomaterials, and silicon-based nanoparticles. Finally, prospects for nanocomposite hydrogel wound dressings are envisaged, providing insights for further research in wound management.
]]>Journal of Composites Science doi: 10.3390/jcs8020045
Authors: Najlaa J. Khalaf Sabrine Ben Amor Borhen Louhichi Jumaa S. Chiad Abdennour Seibi
The optimum structural characteristics of lamination materials used in the fabrication of prosthetic and orthotic parts were investigated in this work. Optimization was chosen based on high yields, ultimate stresses, and bending stress properties. The ideal materials were determined through the use of an RSM (response surface methodology) which considers three factors: Perlon reinforcement, a layer of glass fiber, and the percentage of titanium nanoparticles combined with the matrix laminating resin. The RSM approach suggests thirteen samples by manipulating two variables: the Ti nano percentage and the number of Perlon layers. Laminating materials, defined by RSM methods and treated with a vacuum system, were submitted to a series of tests. The ideal lamination material was compared with the laminations from the initial study through the use of tensile, flexural, and fatigue testing according to ASTM standards. Tests carried out using version 10.0.2 of Design Expert software showed that, compared with the 12 other laminations, the one with 10 Perlon layers and 0.75 percent Ti nano had the highest overall yield and ultimate and bending loads. Fatigue eventually showed that stamina tension constraints were applied for optimal lamination, compared to ten Perlon lamination layers. We additionally tested the fatigue life of the best material and compared it with the available materials used at prosthetics and orthotics centers.
]]>Journal of Composites Science doi: 10.3390/jcs8020044
Authors: Evangelia Delli Dimitrios Gkiliopoulos Evangelia Vouvoudi Dimitrios Bikiaris Konstantinos Chrissafis
Random polypropylene composites reinforced with short glass fibres have been successfully fabricated by melt-mixing. Polypropylene grafted with maleic anhydride (PP-g-MA) was added to the composites, which was expected to act as a compatibilizer and greatly limit the negative effects known to arise from the feeble polymer matrix/glass fibre interfaces. The effect of compatibilizer concentration on the structural, mechanical and thermal behaviour of the composites has been investigated. The results revealed an improvement of the glass fibre/matrix interaction upon the addition of the compatibilizer, which resulted in enhancing the overall material stiffness and the ability of the matrix to store energy. In particular, the lowering of the glass transition and the investigation of the fracture surfaces of the composites confirmed the improved PPR/fibre adhesion. Examination of the tensile elongation indicated the improvement of the Young’s modulus and yield strength with the addition of PP-g-MA, while the storage modulus was also shown to be significantly increased. These results confirmed the versatility and efficiency of the approach presented in this work to improve the thermomechanical properties and sustainability of PPR and promote its usage in industrial applications and commercial manufacturing.
]]>Journal of Composites Science doi: 10.3390/jcs8020043
Authors: Kumudu M. Fernando Chamila A. Gunathilake Chandi Yalegama Upeka K. Samarakoon Chacrawarthige A. N. Fernando Gangani Weerasinghe Geethi K. Pamunuwa Ibrahim Soliman Nomi Ghulamullah Suranga M. Rajapaksha Omar Fatani
Silver nanoparticles (AgNPs) are widely recognized as a prominent antimicrobial agent and have found applications in the field of medicine. This study focuses on the synthesis of AgNPs utilizing the natural reducing agent of Ceylon olive (Elaeocarpus serratus), presenting an economically viable and ecologically friendly approach. For the first time, this research demonstrated the synthesis of AgNPs using phytochemicals extracted from Ceylon olive, serving as both natural reducing and stabilizing agents. The synthesized AgNPs were characterized with UV–visible spectroscopy, a particle size analyzer (PSA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) coupled with an energy dispersive X-ray spectrometer (EDX). The UV–visible spectra primarily indicated the formation of the AgNPs by the surface plasmon resonance band around 434 nm. SEM analysis confirmed the presence of silver nanoparticles within a size range of 50–110 nm, with an average size of approximately 70 nm. FTIR determined that proteins, phenols, and flavonoids may have acted as reducing and capping agents. Experimental parameters were optimized to improve the yield and size of the AgNPs and eventually evaluate their antibacterial properties. The well diffusion method exhibits a significantly larger zone of inhibition for Gram-negative bacterial strains (18.4 ± 0.55 mm for Pseudomonas aeruginosa and 14.4 ± 0.55 mm for Escherichia coli) compared to Gram-positive bacterial strains (11.6 ± 0.55 mm for Staphylococcus aureus and 10.4 ± 0.55 mm for Staphylococcus epidermidis) for 50 µg/mL AgNPs. These findings demonstrate that AgNPs synthesized with Ceylon olive have the potential to develop into novel materials for bacterial-mediated diseases.
]]>Journal of Composites Science doi: 10.3390/jcs8020042
Authors: Aleksandra G. Golubovskaya Tamara S. Kharlamova Ekaterina A. Gavrilenko Elena D. Fakhrutdinova Olga V. Vodyankina Sergei A. Kulinich Valery A. Svetlichnyi
In this work, we studied the catalytic performance of a β-Bi2O3/Bi12SiO20 nanocomposite material in the reactions involving the photodecomposition of rhodamine B and selective photooxidation of 5-hydroxymethylfurfural (HMF). The semiconductor composite nanomaterial was obtained by means of the mechanical grinding of a mixture of nanopowders of β-Bi2O3 and sillenite, both individually produced via pulsed laser ablation. The crystal structure of the prepared composite particles was confirmed by means of X-ray diffraction, while the optical properties of both individual components and their composite (with different ratios of Bi2O3 and Bi12SiO20) were also studied. The photocatalytic activity of the composite particles was studied in the course of their decomposition of rhodamine B under LED excitation at wavelengths of 375, 410 and 470 nm. It was shown that the optimal β-Bi2O3/Bi12SiO20 ratio in the composite particles resulted in their photocatalytic activity exceeding those of both single-phase β-Bi2O3 and Bi12SiO20, as well as that of their mixtures (by ~2.3 times for the excitation of an LED with λ = 375 nm). The novel composite particles were also found to perform better in the selective photocatalytic oxidation of HMF: at a conversion of ~5%, the selectivity toward DFF of the nanocomposite was significantly higher (10.3%) than that of sample Bi2O3 (−4.2%). A model was proposed that explains the increase in activity of the newly prepared photocatalyst due to the formation of a type II heterojunction in its particles.
]]>Journal of Composites Science doi: 10.3390/jcs8020041
Authors: Luana de S. C. Carnaval Amit K. Jaiswal Swarna Jaiswal
In recent years, the increase in the generation of agro-food processing waste, coupled with uncontrolled disposal and inefficient recovery methods, has raised concerns among society, industries, and the research community. This issue is compounded by the accumulation of conventional synthetic packaging. Owing to their significant environmental and economic impacts, the development of sustainable, biocompatible, and biodegradable materials has become an urgent target. In this context, research efforts have been directed toward developing new packaging materials based on renewable sources, such as agro-food waste, contributing to the circular economy concept. However, despite significant advances, novel agro-food-waste-based packaging solutions still largely remain at a laboratory scale. This situation highlights the urgent need for further understanding and thorough investigation into how to upscale these products, thereby promoting engagement, investment, and awareness across various fields. This review aims to discuss the current advances in food packaging development using agro-food waste. It covers the main agro-food wastes and by-products currently recovered for sustainable packaging systems through various approaches, such as the extraction of valuable compounds or waste treatments for incorporation into packaging materials, techniques for their valorization, and recent applications of agro-food waste materials in films and coatings. It also addresses the toxicological and safety approaches, challenges, and future perspectives. After an extensive review, we conclude that current research faces challenges in transitioning novel findings to commercial scale, primarily due to safety factors, high production costs, performance deficits, legislative ambiguities, lack of consumer awareness, and inadequate governmental regulations. Consequently, significant investments in research and development appear to be mandatory in the coming years, aiming for optimized, safe, and cost-effective solutions.
]]>Journal of Composites Science doi: 10.3390/jcs8020040
Authors: Lyazid Bouhala Yao Koutsawa Argyrios Karatrantos Claus Bayreuther
Compressed gas storage of hydrogen has emerged as the preferred choice for fuel cell vehicle manufacturers, as well as for various applications, like road transport and aviation. However, designers face increasing challenges in designing safe and efficient composite overwrapped pressure vessels (COPVs) for hydrogen storage. One challenge lies in the development of precise software programs that consider a multitude of factors associated with the filament winding process. These factors include layer thickness, stacking sequence, and the development of particularly robust models for the dome region. Another challenge is the formulation of predictive behavior and failure models to ensure that COPVs have optimal structural integrity. The present study offers an exploration of numerical methods used in modeling COPVs, aiming to enhance our understanding of their performance characteristics. The methods examined include finite element analysis in Abaqus, involving conventional shell element, continuum shell element, three-dimensional solid element, and homogenization techniques for multilayered composite pressure vessels. Through rigorous comparisons with type-III pressure vessels from the literature, the research highlights the most suitable choice for simulating COPVs and their practicality. Finally, we propose a new design for type-IV hydrogen composite pressure vessels using one explored method, paving the way for future developments in this critical field.
]]>Journal of Composites Science doi: 10.3390/jcs8020039
Authors: Adithya Hegde Rajesh Nayak Gururaj Bolar Raviraj Shetty Rakesh Ranjan Nithesh Naik
Metal matrix composites (MMCs) have achieved significant attention in engineering applications because of their exceptional properties, like increased strength-to-weight ratiosand resistance to wear. However, their manufacturing processes pose challenges for industries, such as oxidation, porosity, and chemical reactions. To address these challenges, this study investigates the processing and sintering (500 °C) of Ti-6Al-4V-SiCp composites and their mechanical properties, particularly hardness, wear and frictional force using a statistical approach. The main objective of this research is to identify optimal processing conditions for Ti-6Al-4V-SiCp composites that yield maximum hardness, minimal wear and frictional force. Thisstudy varies three key parameters, namely compaction pressure (Ton/sq.inch), SiC (wt.%), and PVA binder (wt.%) using Taguchi’s design of experiments (TDOE). Further, the response surface methodology (RSM) is used to develop second-order models to predict the output values under different processing conditions, by correlating with the values obtained from TDOE. The results indicate that the most significant influence on the output is exerted by SiC (wt.%), followed by PVA binder (wt.%) and compaction pressure (Ton/sq.inch). To achieve higher hardness with minimal wear and frictional force during processing, SiCp (15 wt.%), compaction pressure (4 Ton/sq.inch), and PVA binder (3 wt.%) arerecommended. Finally, microstructural analysis using (SEM) scanning electron microscope images, optical macrographs and (AFM) atomic force microscopy revealed that the inclusion of 15 wt.% SiCp resulted in improved hardness, wear and frictional force compared to 20 wt.% SiCp. In conclusion, this study provides valuable insights into optimizing the processing parameters of Ti-6Al-4V-SiCp samples, enabling the production of materials with enhanced hardness and wear resistance.
]]>Journal of Composites Science doi: 10.3390/jcs8020038
Authors: Daniel Campos Pere Maimí Alberto Martín
Friction is a pivotal factor influencing wrinkle formation in composite material shaping processes, particularly in novel thermoplastic composites like polyetheretherketone (PEEK) and low-melting polyaryletherketone (LM-PAEK) matrices reinforced with unidirectional carbon fibers. The aerospace sector lacks comprehensive data on the behavior of these materials under forming conditions, motivating this study’s objective to characterize the interlaminar friction of such high-performance thermoplastic composites across diverse temperatures and forming parameters. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were employed to analyze the thermomechanical behaviors of PEEK and LM-PAEK. These data guided friction tests covering room-to-forming temperatures. Horizontal pull-out fixed-plies tests were conducted to determine the friction coefficient and shear stress dependency concerning temperature, pressure, and pulling rate. Below the melting point, both materials adhered to Coulomb’s law for friction behavior. However, above the melting temperature, PEEK’s friction decreased while LM-PAEK’s friction increased with rising temperatures. These findings highlight the distinct responses of these materials to temperature variations, pulling rates, and pressures, emphasizing the need for further research on friction characterization around glass transition and melting temperatures to enhance our understanding of this phenomenon.
]]>Journal of Composites Science doi: 10.3390/jcs8010037
Authors: Lida Najmi Zhong Hu
Due to their unique properties, carbon nanotubes (CNTs) are finding a growing number of applications across multiple industrial sectors. These properties of CNTs are subject to influence by numerous factors, including the specific chiral structure, length, type of CNTs used, diameter, and temperature. In this topic, the effects of chirality, diameter, and length of single-walled carbon nanotubes (SWNTs) on the thermal properties were studied using the reverse non-equilibrium molecular dynamics (RNEMD) method and the Tersoff interatomic potential of carbon–carbon based on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). For the shorter SWNTs, the effect of chirality on the thermal conductivity is more obvious than for longer SWNTs. Thermal conductivity increases with increasing chiral angle, and armchair SWNTs have higher thermal conductivity than that of zigzag SWNTs. As the tube length becomes longer, the thermal conductivity increases while the effect of chirality on the thermal conductivity decreases. Furthermore, for SWNTs with longer lengths, the thermal conductivity of zigzag SWNTs is higher than that of the armchair SWNTs. Thermal resistance at the nanotube–nanotube interfaces, particularly the effect of CNT overlap length on thermal resistance, was studied. The simulation results were compared with and in agreement with the experimental and simulation results from the literature. The presented approach could be applied to investigate the properties of other advanced materials.
]]>Journal of Composites Science doi: 10.3390/jcs8010036
Authors: Tarek Dayyoub Evgeniy Kolesnikov Olga V. Filippova Sergey D. Kaloshkin Dmitry V. Telyshev Aleksey V. Maksimkin
Preparing a friction pair “polymer-metal” using improved polymeric composites is contemplated a complicated task due to the inert surface of the polymer. Gluing polymer composites with improved mechanical and tribological properties on metals and saving their unique properties at the same time is considered the best way to prepare slide bearing products based on polymer/metal. In this work, ultraviolet initiation is used after a process of mixed acid pre-treatment. The surface of highly oriented films based on ultra-high molecular weight polyethylene (UHMWPE)/graphene nanoplatelets (GNP) is grafted with nanocellulose. The grafting treatment is analyzed using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and contact angle measurements. Mechanical T-peel tests showed that the peel strength for the treated UHMWPE films increased by three times, up to 1.9 kg/cm, in comparison to the untreated films. The tensile strength of the treated UHMWPE films decreased by about 6% to 788 MPa. Tribological tests showed that the values of both friction coefficient and wear intensity of the treated UHMWPE films were increased insignificantly, which were 0.172 and 15.43 µm/m·m2, respectively. The prepared adhesive tape based on UHMWPE films, which can withstand a weight of up to 6 kg per 1 cm2 of the bonded surface, has a low coefficient of friction, high wear resistance, and high strength, and is considered a promising material for preparing slide bearing products.
]]>Journal of Composites Science doi: 10.3390/jcs8010035
Authors: Thomas Zaragkas Spyridon Psarras George Sotiriadis Vassilis Kostopoulos
This study focuses on investigating the behavior of a thermoplastic matrix composite (Carbon Fiber-LMPAEK) under a bearing strength determination test. The specimens were subjected to a double-shear-bolted joint configuration tensile test, and the propagation of damage was monitored using extensometers. The research employs a technique that involves inelastic modelling and considers discrepancies in layer interfaces to better understand bearing damage propagation. In this context, cohesive modelling was utilized in all composite layers, and the Hashin damage propagation law was applied. The double-shear-bolted joint configuration chosen for the test revealed critical insights into the bearing strength determination of the Carbon Fiber-LMPAEK thermoplastic matrix composite. This comprehensive approach, combining inelastic modelling and considerations for layer interfaces, provided a nuanced understanding of the material’s response to bearing forces. The results of the study demonstrated that all specimens exhibited the desired type of bearing failure, characterized by severe delamination around the hole. Interestingly, the thermoplastic matrix composite showcased enhanced bearing properties compared to traditional thermoset materials. This observation underscores the potential advantages of thermoplastic composites in applications requiring robust bearing strength. One noteworthy aspect highlighted by the study is the inadequacy of current aerospace standards in prescribing the accumulation of bearing damage in thermoplastic composites. The research underscores the need for a more strategic modelling approach, particularly in cohesive modelling, to accurately capture the behavior of thermoplastic matrix composites under bearing forces. In summary, this investigation not only provides valuable insights into the bearing strength of Carbon Fiber-LMPAEK thermoplastic matrix composites, but also emphasizes the necessity for refining aerospace standards to address the specific characteristics and failure modes of these advanced materials.
]]>Journal of Composites Science doi: 10.3390/jcs8010034
Authors: Haoting Han Chensong Dong
Composite laminated structural panels are widely used in various industries such as aerospace and machinery because of their light weight, large specific stiffness, and strong fatigue resistance. As a typical engineering structure, the composite stiffened plate is designed to enhance the bearing capacity of the laminated plate. In this study, composite stiffened panels reinforced by carbon and/or E-glass fibres are modelled by finite element analysis (FEA) using Ansys. Nonlinear structural analysis is employed to find the critical buckling load. Three different skin layups, i.e., [45°/−45°/90°/0°]S, [90°/0°/90°/0°]S, and [60°/−30°/90°/0°]S, are studied. For each ply angle combination, different ply material combinations are studied. The cost and weight of each combination formed by applying different ply materials to the skin and stiffeners are studied. The results show that hybrid reinforcement in the stiffened panels reduces costs and maintains high buckling loads. Carbon/epoxy composites as the outer layers also reduce costs and maintain acceptable buckling loads without compromising the overall performance. Customized composite designs in terms of cost and weight can be achieved while maintaining critical buckling loads.
]]>Journal of Composites Science doi: 10.3390/jcs8010033
Authors: Francisca Rocha Sónia Simões
This work comprehensively investigates the production and characterization of an innovative nanocomposite material and an aluminum matrix reinforced with Al2O3 nanoparticles. The powder metallurgy route was used to produce the nanocomposite, and subsequent microstructural and mechanical characterizations were conducted to evaluate its performance. The nanoparticles and metal powders were dispersed and mixed using ultrasonication, followed by cold pressing and sintering. The results indicated that dispersion using isopropanol made it possible to obtain nanocomposites efficiently through powder metallurgy with a high density and an 88% increase in hardness compared to the Al matrix. The process led to the production of nanocomposites with high densification if the volume fraction of the reinforcement did not exceed 1.0 wt.% of Al2O3. The volume fraction of the reinforcement plays an essential role in the microstructure and mechanical properties of the composite because as it increases to values above 1.0 wt.%, it becomes more difficult to disperse through ultrasonication, which results in less promising results. The addition of Al2O3 significantly affects the Al matrix’s microstructure, which influences the mechanical properties. However, this new approach is proving effective in producing Al matrix nanocomposites with high mechanical properties.
]]>Journal of Composites Science doi: 10.3390/jcs8010032
Authors: Balu Alagar Venmathi Maran Sivakamavalli Jeyachandran Masanari Kimura
Polymeric nanofibers have emerged as a captivating medium for crafting structures with biomedical applications. Spinning methods have garnered substantial attention in the context of medical applications and neural tissue engineering, ultimately leading to the production of polymer fibers. In comparison with polymer microfibers, polymer nanofibers boasting nanometer-scale diameters offer significantly larger surface areas, facilitating enhanced surface functionalization. Consequently, polymer nanofiber mats are presently undergoing rigorous evaluation for a myriad of applications, including filters, scaffolds for tissue engineering, protective equipment, reinforcement in composite materials, and sensors. This review offers an exhaustive overview of the latest advancements in polymer nanofiber processing and characterization. Additionally, it engages in a discourse regarding research challenges, forthcoming developments in polymer nanofiber production, and diverse polymer types and its applications. Electrospinning has been used to convert a broad range of polymers into nanoparticle nanofibers, and it may be the only approach with significant potential for industrial manufacturing. The basics of these spinning techniques, highlighting the biomedical uses as well as nanostructured fibers for drug delivery, disease modeling, regenerative medicine, tissue engineering, and bio-sensing have been explored.
]]>Journal of Composites Science doi: 10.3390/jcs8010031
Authors: Prabhakar C. G M Sreenivas Reddy Shashanka Rajendrachari Rayappa Shrinivas Mahale V. Mahesh Anup Pandith
Natural fiber-based composites are highly prioritized in present industries due to their properties and benefits over synthetic fibers. Due to their biodegradable nature, banyan and banana fibers were used for the present work. This paper deals with an experimental and FEA investigation of the tensile and bending behavior of banyan (B) and banana (Ba)-reinforced composites with different volume fractions, such as 25B/25Ba, 30B/20Ba, and 35B/15Ba, with a 50% weight fraction of epoxy resin and different fiber orientations. The hybrid composites treated with a 5% NaOH solution have better results as compared to untreated hybrid composites, with a volume fraction of 30% banyan fibers and 20% banana fiber (30B/20Ba), giving greater tensile and flexural properties for both treated and untreated fiber composites when compared to other volume fraction composites at 0/0/0/0 orientation. The maximum tensile and bending strength was found in the 30B/20Ba volume fractions to be 63.37 MPa and 67.07 MPa, respectively. For treated fiber composites, water absorption increases with an increase in the duration of immersion in composites up to 144 h.
]]>Journal of Composites Science doi: 10.3390/jcs8010030
Authors: Abdelatif Salmi
The present study aims to fill a gap in the literature on the estimation of the bond strength of fiber reinforced polymer sheets bonded to concrete, via the externally bonded reinforcement on grooves (EBROG) technique, employing the curve-fitting on existing datasets in the literature and the methodology of Artificial Neural Networks (ANNs). Therefore, a dataset of 39 experimental results derived from EBROG technique is collected from the literature. A mathematical equation for the bond strength of FRP sheets applied on concrete via the EBROG technique was suggested using curve-fitting and general regression. The proposed mathematical equation is compared and validated with experimental results. The developed ANN model was constructed after testing diverse hidden layers and neurons to find the optimal predictions. The validation of the model is carried out using the experimental results and a statistical analysis is applied to assess the proposed mathematical equation and the proposed ANN model. Furthermore, a parametric study using the ANN model was also performed to investigate the influence of various factors on the bond strength of FRP sheets bonded to concrete. The parametric study proves that the bond strength increases with increasing the tensile stiffness per width, the FRP sheet width, and the concrete compressive strength; however, the effect of the Groove’s width and depth is found to be not monotonous.
]]>Journal of Composites Science doi: 10.3390/jcs8010029
Authors: Noshabah Tabassum Uzaira Rafique Maria Qayyum Abdallah A. A. Mohammed Saira Asif Awais Bokhari
This research paper introduces an innovative methodology to produce biodegradable composite films by combining kaolin, polyvinyl alcohol (PVA), and potato starch (PS) using a solvent casting technique. The novelty of this study resides in the identification and implementation of optimal synthesis conditions, which were achieved by utilizing the Response Surface Methodology—Central Composite Design. The study defines starch, polyvinyl alcohol (PVA), and kaolin as independent variables and examines their influence on important mechanical qualities, water absorption capacity, moisture content, and degradability as primary outcomes. The study establishes the ideal parameters as 5.5 weight percent Kaolin, 2.5 g of starch, and 3.5 g of PVA. These settings yield notable outcomes, including a tensile strength of 26.5 MPa, an elongation at break of 96%, a water absorption capacity of 21%, a moisture content of 3%, and a remarkable degradability of 48%. The study emphasizes that the augmentation of kaolin content has a substantial impact on many properties, including degradability, tensile strength, and elongation at break. Simultaneously, it leads to a reduction in the water absorption capacity and moisture content. The study’s novelty is reinforced by conducting an additional examination on the ideal composite film, which includes investigations using FTIR, TGA, and SEM-EDX techniques. The consistency between the predicted and experimental results is noteworthy, as it provides further validation for the prediction accuracy of Design Expert software’s quadratic equations. These equations effectively capture the complex interactions that exist between process parameters and selected responses. This study presents novel opportunities for the extensive utilization of PVA/PS composite films, including kaolin in various packaging scenarios, thereby significantly advancing sustainable packaging alternatives. The statistical analysis provides strong evidence supporting the relevance of the models, hence increasing our level of trust in the software’s prediction skills. This conclusion is based on a 95% confidence level and p-values that are below a threshold of 0.05.
]]>Journal of Composites Science doi: 10.3390/jcs8010028
Authors: Shivalingayya Gaddimath Shivanand Payamalle Keshavananada Prabhu Channabasavana Hundi Puttaningaiah Jaehyun Hur
Cancer therapy currently focuses on personalized targeted treatments. A promising approach uses stimuli-responsive biomaterials for site-specific drug release, such as pH- and redox-triggered polymer nanocomposites. These materials respond to the tumor microenvironment, enhance efficacy, and reduce off-target effects. Cancer cells with anomalous properties such as acidic cytosolic pH and elevated redox potential are targeted by these biomaterials. An imbalance in ions and biological thiols in the cytoplasm contributes to tumor growth. Functionalized polymer nanocomposites with large surface areas and specific targeting outperform conventional small-molecule materials. To overcome problems such as low bioavailability, uncontrolled drug release, and poor cell penetration, multifunctional nanomaterials make it easier for drugs to enter certain cellular or subcellular systems. High therapeutic efficacy is achieved through surface functionalization, site-specific targeting, and the use of stimuli-responsive components. In particular, pH and redox dual-stimuli-based polymeric nanocomposites for cancer therapeutics have scarcely been reported. This article provides recent progress in pH- and redox-responsive polymer nanocomposites for site-specific drug delivery in cancer therapy. It explores the design principles, fabrication methods, mechanisms of action, and prospects of these dual-stimuli-responsive biomaterials.
]]>Journal of Composites Science doi: 10.3390/jcs8010027
Authors: Vamsi Chakarala Jens Schuster Yousuf Pasha Shaik
Flax–gypsum composites are an emerging class of environmentally friendly materials that combine the mechanical properties of gypsum with the advantageous characteristics of flax fibers. The production of flax–gypsum composites involve the incorporation of flax fibers, derived from the flax plant, into gypsum matrix systems. In order to create a uniform distribution of fibers within the gypsum matrix, the hand lay-up approach has been used to produce the specimens. The fiber content and orientation significantly influence the resulting mechanical and physical properties of the composites. Various tests were conducted on the samples, such as a flexural test, a compression test, a density test, a water absorption test, and a microscopy test. The addition of flax fibers imparts several desirable properties to the gypsum matrix. When combined with gypsum, these fibers enhanced the composite’s mechanical properties, such as flexural strength and compressive strength. The results indicated improved compression and flexural strengths due to effective load transfer within the matrix, for up to 10% of fiber loading. A decrease in composite density upon flax fiber addition results in a lighter material, enabling insights for various applications.
]]>Journal of Composites Science doi: 10.3390/jcs8010026
Authors: Filip Brleković Katarina Mužina Stanislav Kurajica
The aim of this work was to determine how different types of alkaline pretreatment influence the properties of waste almond and hazelnut nutshell, as well as their compatibility with model inorganic geopolymer matrixes for the formation of biocomposites with potential use in civil engineering. For alkaline pretreatment, 3, 6 and 9% NaOH water solutions and milk of lime were used under different temperature and time conditions. The rise in the crystallinity index was confirmed by X-ray powder diffraction analysis, while the corroboration of the removal of amorphous and undesirable components was demonstrated through Fourier-transform infrared spectroscopy. Furthermore, the effectiveness of the pretreatments was confirmed via simultaneous differential thermal and thermogravimetric analysis, and the positive change in the morphology of the surface of the waste nutshell (WN) and the deposition of the desired phases was established using scanning electron microscopy. Surface free energy and adhesion parameters were calculated using the Owens, Wendt, Rabel and Kaelble method for WN as fillers and geopolymers as model novel inorganic binders. This research indicates that the 6% NaOH treatment is the optimal pretreatment process for preparing WN as the filler in combination with potassium and metakaolin geopolymer that has been cured at room temperature.
]]>Journal of Composites Science doi: 10.3390/jcs8010025
Authors: Zachary Safford Mohammed Shonar Vijaya Chalivendra
An experimental study is performed to investigate the quasi-static fracture toughness and damage monitoring capabilities of liquid metal (75.5% Gallium/24.5% Indium) reinforced intraply glass/carbon hybrid composites. Two different layups (G-0, where glass fibers are along the crack propagation direction; C-0, where carbon fibers are along the crack propagation direction) and two different weight percentages of liquid metal (1% and 2%) are considered in the fabrication of the composites. A novel four-probe technique is employed to determine the piezo-resistive damage response under mode-I fracture loading conditions. The effect of layups and liquid metal concentrations on fracture toughness and changes in piezo-resistance response is discussed. The C-composite without liquid metal demonstrated higher fracture toughness compared to that of the G-composite due to carbon fiber breakage. The addition of liquid metal decreases the fracture initiation toughness of both G- and C-composites. Scanning electron microscopy images show that liquid metal takes the form of large liquid metal pockets and small spherical droplets on the fracture surfaces. In both C- and G-composites, the peak resistance change of composites with 2% liquid metal is substantially lower than that of both no-liquid metal and 1% liquid metal composites.
]]>Journal of Composites Science doi: 10.3390/jcs8010024
Authors: Ahmed A. Alshahrani Abeer A. El-Habeeb Arwa A. Almutairi Dimah A. Almuaither Sara A. Abudajeen Hassan M. A. Hassan Ibrahim Hotan Alsohaimi
Amidst the ongoing advancements in membrane technology, a leading method has come to the forefront. Recent research has emphasized the substantial influence of surface attributes in augmenting the effectiveness of thin-film membranes in water treatments. These studies reveal how surface properties play a crucial role in optimizing the performance of these membranes, further establishing their prominence in the field of membrane technology. This recognition stems from the precise engineering of surfaces, ensuring they meet the demanding requirements of advanced separation processes. This study utilizes polyamide as a discerning layer, applied atop a polysulfone support sheet through interfacial polymerization (IP) for membrane fabrication. The amounts in the various membranes were created to vary. The membrane’s permeability to water with significant salt rejection was enhanced, which improved its effectiveness. The polyamide (PA) membrane comprising graphene oxide (rGO, 0.015%) had a water permeability of 48.90 L/m2 h at 22 bar, which was much higher than the mean permeability of polyamide membranes (25.0 L/m2 h at 22 bar). On the other hand, the PA–rGO/CHIT membranes exhibited the lowest water permeability due to their decreased surface roughness. However, the membranes’ effectiveness in rejecting salts ranged from 80% to 95% for PA–rGO and PA–rGO/CHIT membranes.
]]>Journal of Composites Science doi: 10.3390/jcs8010023
Authors: Michael Ong Arlindo Silva
Sandwich composites are often used as primary load-bearing structures in various industries like aviation, wind, and marine due to their high strength-to-weight and stiffness-to-weight ratios, but they are vulnerable to damage from Low-velocity-impact (LVI) events like dropped tools, hail, and birdstrikes. This often manifests in the form of Facesheet-Core-Debonding (FCD) and is often termed Barely-Visible-Impact-Damage (BVID), which is difficult to detect and can considerably reduce mechanical properties. In general, a balsa core sandwich is especially vulnerable to FCD under LVI as it has poorer adhesion than synthetic core materials. A cork core sandwich does show promise in absorbing LVI with low permanent indentation depth. This paper also reviews surface treatment/modification as a means of improving the adhesion of composite core and fiber materials: key concepts involved, a comparison of surface free energies of various materials, and research literature on surface modification of cork, glass, and carbon fibers. Since both balsa and cork have a relatively low surface free energy compared to other materials, this paper concludes that it may be possible to use surface modification techniques to boost adhesion and thus FCD on balsa or cork sandwich composites under LVI, which has not been covered by existing research literature.
]]>Journal of Composites Science doi: 10.3390/jcs8010022
Authors: Kam-Che Lui Xungai Wang Chi-Wai Kan
Conventional scar treatment options of single pressure garment therapy (PGT) or silicone gel sheeting (SGS, Cica-Care®, Smith and Nephew, London, UK) alone lack mechanical property tunability. This article discusses a scar healing composite (PGF-Biopor®AB, Dreve Otoplastik GmbH, Unna, Germany) and how its mechanical properties can be tuned for improved mechanotherapy. A balance between compression and tension was achieved by tuning the tensile and shear properties, facilitating tension shielding and pressure redistribution for scar therapeutics. Biopor®AB-wrapping on biaxial-tensioned pressure garment fabric (PGF) allowed compression therapy and internal pressure redistribution. The Biopor®AB surface, with a coefficient of friction close to 1, strategically localizes stress for effective tension shielding. A substantial five-fold reduction in silicone tension, amounting to 1.060 N, achieves tension shielding and pressure redistribution. Simultaneously, a dynamic internal pressure-sharing mechanism distributes 0.222 kPa from each SPK-filament bundle, effectively managing internal pressure. Alongside the principle compression-silicone dual therapy, this composite design with dynamic internal pressure sharing and mechanical property tunability provides an additional pressure-relieving strategy for multiple scar therapeutics.
]]>Journal of Composites Science doi: 10.3390/jcs8010021
Authors: Miguel A. R. Pereira Ivan Galvão José Domingos Costa Rui M. Leal Ana M. Amaro
The joining of aluminium alloy AA6082-T6 to polyamide 6 (PA6) by friction stir spot welding (FSSW) was investigated in the current work. Although previous studies can be found on the joining of polymers and metals by FSSW, welding using aluminium plates as thin as the ones used in this work (1 mm) was not found. The influence of the plunge depth (0.1 to 0.5 mm) and the dwell time (15 and 30 s) parameters on the welding results was studied. In general, the increase of these parameters led to the improvement of the maximum load of the joints under tensile-shear testing. Additionally, the feasibility of multiple spot welding was tested and proven. Finally, although most of the welds were performed with a pinless tool, a tool with a conical pin and a concave shoulder was used for comparison. The use of this more conventional tool resulted in joints easily broken by handling. Still, the potential of the conical pin tool was demonstrated. The different conditions were evaluated based on morphology and tensile-shear testing. The weld with the best mechanical behaviour was produced with multiple spot welding, which failed for a maximum load of about 2350 N.
]]>Journal of Composites Science doi: 10.3390/jcs8010020
Authors: Murthy BRN Rajendra Beedu Jayashree P K Srinivasa Rao Potti
Abrasive Water Jet Machining (AWJM) is a popular machining method used to machine polymer matrix composites that are sensitive to temperature. This method is non-thermal, and each input parameter has a significant effect on output parameters, such as material removal rate, kerf width, surface roughness, and the potential for delamination. To ensure high-quality machining, it is crucial to set these input parameters at their optimal level. This paper proposes a simple approach to predict the optimum process parameters of water jet machining operations on jute fiber-reinforced polymer composite (JFRPC). The process parameters considered are standoff distance (SOD), traverse speed (TS), and abrasive material flow rate (MFR). Conversely, surface roughness (Ra) and delamination (Da) are the output parameters. Process parameters are set using Taguchi’s L27 array, with consideration given to three levels of each input parameter. The best value for process parameters is found using grey relational analysis (GRA), and an ANOVA on GRA illustrates the impact of each input variable. After a confirmation test, it was found that the suggested parameters guarantee the best possible results.
]]>Journal of Composites Science doi: 10.3390/jcs8010019
Authors: Yu-Lun Su Shuo-En Yu I-Chih Ni Chih-I Wu Yong-Song Chen Yi-Cheng Chuang I-Chun Cheng Jian-Zhang Chen
Ar, Ar/H2 (95:5), and Ar/O2 (95:5) plasmas are used for treating the NiCo metal–organic framework (MOF), and the plasma-processed NiCo MOF is applied for catalyzing the oxygen evolution reaction (OER) in a 1 M KOH electrolyte. Linear sweep voltammetry measurements show that after plasma treatment with Ar/H2 (95:5) and Ar gases, the overpotential reaches 552 and 540 mV, respectively, at a current density of 100 mA/cm2. The increase in the double-layer capacitance further confirms the enhanced oxygen production activity. We test the Ar plasma-treated NiCo MOF as an electrocatalyst at the OER electrode and Ru as an electrocatalyst at the hydrogen evolution reaction (HER) electrode in the alkaline water electrolysis module. The energy efficiency of the electrolyzer with the Ar plasma-processed NiCo-MOF catalyst increases from 54.7% to 62.5% at a current density of 500 mA/cm2 at 25 °C. The alkaline water electrolysis module with the Ar plasma-processed catalyst also exhibits a specific energy consumption of 5.20 kWh/m3 and 4.69 kWh/m3 at 25 °C and 70 °C, respectively. The alkaline water electrolysis module performance parameters such as the hydrogen production rate, specific energy consumption, and energy efficiency are characterized at temperatures between 25 °C and 70 °C. Our experimental results show that the NiCo MOF is an efficient OER electrocatalyst for the alkaline water electrolysis module.
]]>Journal of Composites Science doi: 10.3390/jcs8010018
Authors: Temuri Latsuzbaya Peter Middendorf Dietmar Voelkle Christoph Weber
The application of fiber-reinforced thermoplastic mono-material sandwich panels has many advantages, such as recyclability, reduction in processing cycle times, integration of additional elements by means of welding, and a great potential for in-line production. The most efficient way to produce a curved thermoplastic sandwich panel is thermoforming, which has several challenges. One of them is to achieve a higher thermal gradient in the panel. On the one hand, the temperature at the skin–core interface must exceed the softening point of the polymer to reach a sufficient bonding degree. On the other hand, the core should not be overheated and overloaded to avoid its collapse. Furthermore, several fiber distortions, such as wrinkles or buckles, can be developed during thermoforming. All these flaws have a negative impact on the mechanical performance of the sandwich structure. The objective of this study is the development of a simulation tool for the thermoforming process, which can replace the time-consuming trial-and-error-based method. Therefore, a coupled thermomechanical model was developed for a novel thermoplastic sandwich structure, which is able to predict the temperature distribution and its influence on the mechanical properties of the panel. Experimental trials were conducted to validate the thermomechanical forming model, which demonstrated a good agreement with numerical results.
]]>Journal of Composites Science doi: 10.3390/jcs8010017
Authors: Zaida Ortega Luis Suárez Jake Kelly-Walley Paul R. Hanna Mark McCourt Bronagh Millar
Rotational molding advantages include the production of a hollow part with no welding lines, either of small or big sizes, with no internal stresses and good surface details. However, the process is limited by the long cycle times, and its related high energy consumption. Different strategies can be followed to reduce such energy use. This work assesses the use of pressure inside the molds during the densification and cooling stages, finding reductions in overall cycle time of approximately 20%, because of the reduction in the heating time required but also to the increased cooling rate. The influence of such an approach on the production of composites with reed fibers has also been assessed, finding a similar trend towards cycle time reductions. The rotomolded samples’ thermomechanical and rheological behavior were determined, finding that viscosity was not affected due to the incorporation of air during the moldings; besides, the homogeneity of the composites increased due to the mold pressurization. The parts obtained show good aesthetics and good thermomechanical behavior along the entire temperature range studied, and particularly for 10% composites; higher fiber ratios should be prepared via melt compounding. Therefore, the mold pressurization allows us to reduce both oven and cooling times, which can be translated into an increase in productivity and a decrease in energy consumption, which are undeniably related to the increase in the products’ sustainability and cost.
]]>Journal of Composites Science doi: 10.3390/jcs8010016
Authors: Simon Sanchez-Diaz Saïd Elkoun Mathieu Robert
This study investigated the influence of fiber content, temperature, and relative humidity on the thermal insulation properties of nonwoven mats made of seed fibers from Asclepias Syriaca, commonly known as milkweed floss. Nonwoven mats with a 1-inch thickness were produced by uniformly arranging milkweed fibers within a mold. Various quantities of fiber were employed to obtain nonwoven mats with a fiber content ranging from 5 to 35 kg/m3. Thermal conductivity and thermal diffusivity were measured across diverse relative humidity levels and temperatures. Simultaneously, milkweed floss samples were exposed to identical environmental conditions to assess the moisture regain and specific heat capacities of the fiber. The specific heat capacity of milkweed and thermal conductivity of the nonwovens exhibited a linear increase with temperature. The thermal diffusivity and thermal conductivity of the nonwovens decreased with rising fiber content. The thermal insulation properties of the nonwovens remained partially stable below 30% relative humidity but substantially deteriorated at higher levels. The nonwovens exhibited optimal thermal insulation properties at a fiber content between 20 and 25 kg/m3. The results of this study highlighted several technical advantages of employing milkweed floss as a sustainable and lightweight solution for thermal insulation.
]]>Journal of Composites Science doi: 10.3390/jcs8010015
Authors: Masoume Ehsani Heloisa Westphalen Huu Doan Ali Lohi Amira Abdelrasoul
Plant-based proteins are gaining popularity because of their appeal to vegetarians and vegans, alignment with scientific and regulatory recommendations, and the environmental impact associated with livestock production. Several techniques are employed for the separation, isolation, and purification of plant-based proteins including membrane-based separation, diafiltration, centrifugation, chromatography, electrophoresis, micellar precipitation, and isoelectric precipitation. Despite decades of application, these techniques still have some limitations such as scale-up challenges, high solvent consumption, chemical/biological disposal, and the possibility of protein loss during precipitation or elution. Membrane separation processes are the most effective purification/concentration technology in the production of plant-based protein isolates and concentrates due to their selective separation, simple operational conditions, and easy automation. Membrane separation processes yielded products with higher protein content compared to isoelectric precipitation, and all concentrates presented good functional properties with expected variability among different legumes. This review critically focuses on the membrane technology advances and challenges for the purification of plant-based protein isolates. This study also highlights the plant-based diet trend, the market, composition, and the protein isolate of the faba bean, in addition to the emerging technologies for the elimination of antinutritional compounds.
]]>Journal of Composites Science doi: 10.3390/jcs8010013
Authors: Yihao Zhang Ning Kang Shipu Jiao Yang Li Xu Zhang Xianhua Liu
The pyrolysis of metal-organic frameworks (MOFs) is a popular strategy for the synthesis of nanoporous structures. Polymetallic oxides (POMs) are a class of polyhedral structural compounds with unique physicochemical properties. Little effort has been paid to evaluate MOF-POM hybrid-derived materials for peroxomonosulfate (PMS) activation. In this study, a cobalt-based MOF, ZIF-67, together with three types of POMs (phosphomolybdic acid, silicotungstic acid, and phosphotungstic acid), were used as precursors for the synthesis of PMS activation catalyst via pyrolysis. Three T-POMs@ZIF-67 nanohybrids (T-PMo@ZIF-67, T-SiW@ZIF-67, and T-PW@ZIF-67) were obtained by pyrolyzing the prepared precursors at 500 °C. Furthermore, the prepared T-POMs@ZIF-67 nanomaterials were evaluated for the catalytic activation of PMS in the degradation of levofloxacin (LEV). The results showed that the LEV degradation rate could reach 91.46% within 30 min under the optimized conditions when T-PW@ZIF-67 was used as the PMS activation catalyst. The catalytic efficiency of the catalyst decreased by only 9.63% after five cycles, indicating that the material has good stability. This work demonstrates the great potential of POMs@MOF derivatives for application in the field of wastewater treatment.
]]>Journal of Composites Science doi: 10.3390/jcs8010014
Authors: Andres Arce Panagiotis Kapsalis Catherine G. Papanicolaou Thanasis C. Triantafillou
This paper discusses the integration of an alkali-activated mortar (AAM), based on industrial waste, into a novel composite material fit for structural upgrading purposes and rendered with high temperature endurance and a low CO2 footprint. The AAM combined with carbon fiber textiles form a new generation of sustainable inorganic matrix composites—that of textile-reinforced alkali-activated mortars (TRAAM). A test program was designed to assess the effectiveness of carbon TRAAM overlays in increasing the shear capacity of masonry wall specimens comprising solid clay bricks bonded with lime-based mortar and furnished with TRAAM jackets on both sides. The initial and the residual capacity of the reinforced walls were evaluated, the latter by performing diagonal compression tests after exposure to 300 °C and 550 °C. It was shown that TRAAM jacketing can increase the shear capacity of unfired masonry walls by 260% and 335% when a single or a double layer of textile is used, respectively. Rapid heating to temperatures up to 550 °C, one-hour-long steady-state heating, and natural cooling bore no visible thermal cracks on the specimens and had little effect on their residual capacity. Based on these results, the prospect of using TRAAM for retrofitting applications for fire-resilient structures seems very auspicious.
]]>Journal of Composites Science doi: 10.3390/jcs8010012
Authors: Moises Jimenez-Martinez Julio Varela-Soriano Julio S. De La Trinidad-Rendon Sergio G. Torres-Cedillo Jacinto Cortés-Pérez Manuel Coca-Gonzalez
The transformation of powertrains, powered by internal combustion engines, into electrical systems generates new challenges in developing lightweight materials because electric vehicles are typically heavy. It is therefore important to develop new vehicles and seek more aesthetic and environmentally friendly designs whilst integrating manufacturing processes that contribute to reducing the carbon footprint. At the same time, this research explores the development of new prototypes and custom components using printed composite materials. In this framework, it is essential to formulate new approaches to estimate fatigue life, specifically for components tailored and fabricated with these kinds of advanced materials. This study introduces a novel fatigue life prediction approach based on an artificial neural network. When presented with given inputs, this neural network is trained to predict the accumulation of fatigue damage and the temperature generated during cyclic loading, along with the mechanical properties of the compound. Its validation involves comparing the network’s response with the load ratio result, which can be calculated using the fatigue damage parameter. Comparing both results, the network can successfully predict the fatigue damage accumulation; this implies an ability to directly employ data on the mechanical behavior of the component, eliminating the necessity for experimental testing. Then, the current study introduces a neural network designed to predict the accumulated fatigue damage in printed composite materials with an Onyx matrix and Kevlar reinforcement.
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Authors: Alberto D’Amore Luigi Grassia
This paper discusses the theoretical and experimental correlations between fatigue and static strength statistical distributions. We use a two-parameter residual strength model that obeys the qualitative strength-life equal rank assumption (SLERA) for guidance. The modeling approach consists of recovering the model’s parameters by best fitting the constant amplitude (CA) fatigue data at a given stress ratio, R, and the experimental Weibull parameters of the static strength distribution function. An extensive set of fatigue life and residual strength data for AS4 carbon/epoxy 3k/E7K8 Plain Weave Fabric with [45/−45/90/45/−45/45/−45/0/45/−45]S layups, obtained at different stress ratios, R, have been analyzed. The modeling approach consists of recovering the model’s parameters from pure tension or compression fatigue data at R = 0.1 and R = 5, respectively. Once the parameters are fixed, the model’s capabilities, potential, and limits are discussed by comparing its predictions with residual strength and fatigue life data obtained at stress ratios with mixed tension/compression loadings, namely R = −0,2 and R = −1. Moreover, from a preliminary analysis, the theoretical extension of the model’s capabilities to variable amplitude loadings is conceptualized. The application of Miner’s rule is also discussed and compared with a new damage rule to analyze the fatigue responses under variable amplitude loadings.
]]>Journal of Composites Science doi: 10.3390/jcs8010010
Authors: Francisco Vale Raquel Travassos Mariana Diogo Pinto Madalena Prata Ribeiro Filipa Marques Amílcar Ramalho Pedro Antunes Carlos Miguel Marto Anabela Baptista Paula Catarina Nunes Inês Francisco
Adhesion between orthodontic brackets and conditioned enamel surfaces is essential for treatment success with fixed appliances. During treatment, enamel demineralization lesions commonly appear although remineralization is possible through fluoride application. Aim: Evaluation of the surface rugosity in bracket rebonding, specifically the influence of fluoride application before the bonding protocol. In total, 30 human premolars extracted for orthodontic reasons were used and divided into three groups. The control group was not submitted to any experimental manipulation; group 1 and 2 were placed in a demineralization solution and group 2 was additionally subjected to a subsequent fluoride application. The surface rugosity was measured at different timings: T0—before bracket bonding; T1—first bracket debonding after composite removal; and T2—second bracket debonding after composite removal. For the statistical analysis, the Kruskal–Wallis test, Mann-Whitney test, and Student’s t-test were used. Regarding the comparison between groups, at T0 and T1, no statistically significant differences were observed. However, at T2, statistically significant differences were verified between the control group and group 1 for the parameters: Ra (p = 0.0043), Rq (p = 0.0043), Rqmax (p = 0.0043), Rp (p = 0.0087), and Rv (p = 0.026). Regarding the evaluation between time points, in the control group, no statistically significant differences were observed. In group 1, statistically significant results were found between T0 and T1 for the parameters: Rq (p = 0.0451), Rqmax (p = 0.0451), Rp (p = 0.0091), and Rvk (p = 0.0433) and between T1 and T2 for the parameters: Ra (p = 0.0465), Rq (p = 0.0433), Rqmax (p = 0.0433), and Rp (p = 0.0155). In group 2, statistically significant differences were found between T0 and T1 for the parameter Rvk (p = 0.0405). A decrease In surface rugosity was observed during multiple bracket rebonding procedures. Therefore, this study suggests that rebonding procedures alter the enamel surface rugosity. The need for rebonding should be avoided, opting for a more effective and correct first bonding. In the case of multiple rebonding, enamel remineralization maneuvers must be applied to recover the surface, since the results of this study suggest that the application of fluoride prior to bracket adhesion promotes lower surface roughness.
]]>Journal of Composites Science doi: 10.3390/jcs8010009
Authors: Michela Saracco Vincenzo Ciriello Antonio Spinarelli Giuseppe Solarino Remo Goderecci Giandomenico Logroscino
Hip replacement has significantly improved the quality of life of patients with symptomatic hip osteoarthritis. Various bearings have been developed over the years. Each of these has advantages and disadvantages. On the one hand, Metal-on-Metal (MoM) has been associated with a high level of wear and metal ion release of chromium (Cr) and cobalt (Co). On the other hand, Ceramic-on-Ceramic (CoC) bearings, known to have a wear rate close to zero, have been associated with an increased risk of squeaking and component fracture. Ceramic-on-Metal (CoM), a hybrid hard-on-hard bearing, was proposed to overcome the CoC and MoM limits. Preliminary clinical and radiographical results have been described as favourable. Due to the failure of MoM and the increased risk of ion release and metal toxicity, CoM was withdrawn from the market without causing significant clinical complications. Data from the literature showed that CoM bearings are reliable and safe at medium- and long-term follow-up, if correctly implanted. In this narrative review, we analysed the real risks and benefits associated with the implantation of CoM bearings.
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Authors: Tomoki Miyashita Kenichi Katabira Hiroki Kurita Fumio Narita
As sensor materials for structural health monitoring (SHM, a nondestructive test for the continuous evaluation of the conditions of individual structural components and entire assemblies), magnetostrictive materials, piezoelectric materials, and optical fibers have attracted significant interest. In this study, the mode I interlaminar fracture load and crack self-detection potential of glass fiber-reinforced polymer (GFRP)–embedded magnetostrictive Fe–Co fibers were investigated via double cantilever beam testing. The results indicated that by controlling the amount of Fe–Co fibers introduced into GFRP, the number of Fe–Co fibers could be reduced without compromising the performance of GFRP. Furthermore, the magnetic flux density increased significantly with crack propagation, indicating that the magnetic flux density change could determine crack propagation.
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