Journal of Composites Science

18 pages, 3492 KiB

Open AccessArticle

Physical Foam Injection Molding of Cellulose Fiber Reinforced Polypropylene by Using CO₂: Parameter Variation and Comparison to Chemical Foam Injection Molding

by Claudia Pretschuh, Matthias Mihalic, Christian Sponner, Thomas Lummerstorfer, Andreas Steurer and Christoph Unterweger

J. Compos. Sci. 2025, 9(1), 50; https://doi.org/10.3390/jcs9010050 - 20 Jan 2025

Viewed by 532

Abstract

The use of cellulose fiber-filled polypropylene (PP) composites in combination with foam injection molding has enabled the lightweight design of injection-molded parts. The study provides achievements for the physical foam injection molding (MuCell^®) process of PP–cellulose fiber compounds by using CO [...] Read more.

The use of cellulose fiber-filled polypropylene (PP) composites in combination with foam injection molding has enabled the lightweight design of injection-molded parts. The study provides achievements for the physical foam injection molding (MuCell^®) process of PP–cellulose fiber compounds by using CO₂ as the direct foaming agent, including a comparison of MuCell^® foaming with N₂ and a comparison to a chemical foaming process. Weight and density reductions, foam structure and specific mechanical properties are highly dependent on the applied processing parameters. The maximum weight reduction reached values of up to 16%, and density reduction even reached 33% in relation to the compact plates. The extent of weight and density reduction could be adjusted, among other factors, by a reduction in the shot volume. Setting the density reduction to 22% allowed for simultaneously decreasing weight while sustaining the specific flexural properties and limiting the loss of specific impact strength. By using optimized FIM parameters, the mechanical performance could be improved, with specific modulus values even outperforming the compact reference sample. This presents a significant benefit for the preparation of lightweight products and sets the basis for further optimization and modeling studies. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

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8 pages, 5916 KiB

Open AccessArticle

RF Dielectric Permittivity Sensing of Molecular Spin State Switching Using a Tunnel Diode Oscillator

by Ion Soroceanu, Andrei Diaconu, Viorela-Gabriela Ciobanu, Lionel Salmon, Gábor Molnár and Aurelian Rotaru

J. Compos. Sci. 2025, 9(1), 49; https://doi.org/10.3390/jcs9010049 - 20 Jan 2025

Viewed by 392

Abstract

We introduce a novel approach to study the dielectric permittivity of spin crossover (SCO) molecular materials using a radio frequency (RF) resonant tunnel diode oscillator (TDO) circuit. By fabricating a parallel plate capacitor using SCO particles embedded into a polymer matrix as an [...] Read more.

We introduce a novel approach to study the dielectric permittivity of spin crossover (SCO) molecular materials using a radio frequency (RF) resonant tunnel diode oscillator (TDO) circuit. By fabricating a parallel plate capacitor using SCO particles embedded into a polymer matrix as an integral part of the inductor (L) capacitor (C) LC tank of the TDO, we were able to extract the temperature dependence of the dielectric permittivity of frequency measurements for a wide selection of resonance values, spanning from 100 kHz up to 50 MHz, with great precision (less than 2 ppm) and in a broad temperature range. By making use of this simple electronic circuit to explore the frequency and temperature-dependent dielectric permittivity of the compound Fe[(Htrz)₂(trz)](BF₄), we demonstrate the reliability and resolution of the technique and show how the results compare with those obtained using complex instrumentation. Full article

(This article belongs to the Topic Advanced Polymeric Composites: Processing, Characterization and Mechanical Behavior)

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18 pages, 2875 KiB

Open AccessReview

Enhancing Mechanical Properties of Polyamide 66 with Carbon-Based Nano-Fillers: A Review

by Matija Avbar, Gean Henrique Marcatto de Oliveira and Sergio de Traglia Amancio-Filho

J. Compos. Sci. 2025, 9(1), 48; https://doi.org/10.3390/jcs9010048 - 19 Jan 2025

Viewed by 311

Abstract

Carbon-based nanofillers have emerged as promising agents for enhancing the mechanical properties of polyamide 66 (PA66). This literature review emphasizes the increasing interest in nanocomposites due to their ability to significantly improve material properties, often surpassing traditional short fiber reinforced polymers, even at [...] Read more.

Carbon-based nanofillers have emerged as promising agents for enhancing the mechanical properties of polyamide 66 (PA66). This literature review emphasizes the increasing interest in nanocomposites due to their ability to significantly improve material properties, often surpassing traditional short fiber reinforced polymers, even at low nanofiller loadings. Across the studies reviewed, consistent enhancements in various quasi-static mechanical properties are observed upon the incorporation of nanofillers. Optimal carbon-based nanofiller loadings typically fall within the range of 0.25% to 1 wt%. Notably, significant improvements have been reported, with increases of up to 78% in Young’s modulus (E) and 138% in ultimate tensile strength (UTS). This comprehensive analysis highlights the potential of carbon-based nanofillers in enhancing the performance of polyamide 66, offering valuable insights for the design and development of advanced nanocomposite materials. Preliminary test results by the authors, where melt mixing was employed to produce PA66 carbon nanotube (CNT) nanocomposites with loadings of up to 1 wt%, show an increase in Young’s modulus whilst the ultimate tensile strength and strain at break (SaB) are reduced. Full article

(This article belongs to the Section Nanocomposites)

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21 pages, 3908 KiB

Open AccessReview

Stability Improvement of Irradiated Polymer Composites by Inorganic Compounds—A Pertinent Solution with Respect to Phenolic Antioxidants

by Traian Zaharescu and Ademar B. Lugāo

J. Compos. Sci. 2025, 9(1), 47; https://doi.org/10.3390/jcs9010047 - 19 Jan 2025

Viewed by 624

Abstract

The long-term usage of polymer products necessitates addressing the appropriate preservation of their low oxidation state that extends the warranty period. The addition of pertinent stabilization components into the composite formulations (synthesis and natural antioxidants, pristine and doped oxides, clays or couples of [...] Read more.

The long-term usage of polymer products necessitates addressing the appropriate preservation of their low oxidation state that extends the warranty period. The addition of pertinent stabilization components into the composite formulations (synthesis and natural antioxidants, pristine and doped oxides, clays or couples of them) produces an improvement in the kinetic parameters characterizing the accelerated degradation that occurs during high-energy exposures. The competition between the material ageing and the mitigation of oxidation is controlled by the protection efficiency. In this paper, the main advantages of inorganic structures in comparison to classical organic antioxidants are emphasized. A significant improvement in stability, simultaneously associated with the enhancing of functional characteristics, the lack of migration, low cost and easy accessibility, make the reevaluation of certain fillers as stabilizers appropriate. The correlation between the functional properties and the filler nature in polymer materials may be reconsidered for the assessment of the participation capability of inorganic structures in the inhibition of oxidation by the inactivation of free radicals. The lifetimes of degradation intermediates extended by the activities of inorganic compounds are increased by means of electrical interactions involving the unpaired electrons of molecular fragments. These physical contributions are reflected in chemical stability. An essential feature for the presented inorganic options is a strong impact on the recycling technologies of polymers by radiation processing. Plastic products, including all categories of macromolecular materials, can gain an increased durability through the inorganic alternative of protection. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

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18 pages, 23441 KiB

Open AccessArticle

Evaluation of the Reinforcing Effect of Intermetallic and Ceramic Phases in a WE54-15%(Vol.%)SiC_w Composite Using In Situ Synchrotron Radiation Diffraction

by Gerardo Garces, Pablo Pérez, Judit Medina and Paloma Adeva

J. Compos. Sci. 2025, 9(1), 46; https://doi.org/10.3390/jcs9010046 - 18 Jan 2025

Viewed by 338

Abstract

The reinforcing effect of β-Mg₁₄YNd₂ precipitates and SiC whiskers has been evaluated in a WE54-15%(vol.%)SiC_w composite using synchrotron radiation diffraction during compression tests from room temperature to 300 °C. The addition of SiC whiskers slightly increases the yield stress [...] Read more.

The reinforcing effect of β-Mg₁₄YNd₂ precipitates and SiC whiskers has been evaluated in a WE54-15%(vol.%)SiC_w composite using synchrotron radiation diffraction during compression tests from room temperature to 300 °C. The addition of SiC whiskers slightly increases the yield stress compared to an unreinforced WE54 alloy. However, whiskers are not effective in increasing the temperature at which the mechanical strength of the unreinforced WE54 alloy begins to decay. The plastic deformation process is controlled by the magnesium matrix over the entire compression temperature range. On one hand, β-Mg₁₄YNd₂ precipitates assume an additional transferred load from the magnesium matrix just after the yield point in both the WE54 alloy and WE54-15%SiC_w composite. The magnitude of transferred load becomes smaller as the temperature increases due to the relaxation process around precipitates. On the other hand, the reinforcing effect of SiC whiskers is greater than that of β-Mg₁₄YNd₂ precipitates, although its effect also tends to disappear at temperatures equal to or higher than 200 °C. Full article

(This article belongs to the Section Composites Modelling and Characterization)

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23 pages, 5651 KiB

Open AccessArticle

The Ultimate Tensile Strength of SiC/SiC Composites: Multiscale Approach

by Jacques Lamon

J. Compos. Sci. 2025, 9(1), 45; https://doi.org/10.3390/jcs9010045 - 17 Jan 2025

Viewed by 412

Abstract

The present paper tackles the important issue of tensile ultimate strength of ceramic matrix composites, using a multiscale approach. The ultimate strength is investigated at the successive increasing length scales inherent to 2D woven SiC/SiC composites, i.e., single filaments, fibre tow, unidirectional composite [...] Read more.

The present paper tackles the important issue of tensile ultimate strength of ceramic matrix composites, using a multiscale approach. The ultimate strength is investigated at the successive increasing length scales inherent to 2D woven SiC/SiC composites, i.e., single filaments, fibre tow, unidirectional composite (minicomposites), and 2D woven composite. First, experimental results on tensile behavior under strain-controlled conditions are summarized for tows, minicomposites, and composites. Then, models of tow ultimate failures under controlled force and strain are presented. The exact criterion of tow failure is developed for filament fracture initiation and then propagation based on applied stress and on filament strength gradient. The model of the ultimate failure of the composite under strain-controlled conditions is based on the strength of filaments in the presence of matrix cracks and the overstress induced by interactions of broken filaments and the matrix. The variability of ultimate strengths of filaments, minicomposites, and composites at various gauge lengths is described by linear p-quantile diagrams, which indicates that the data follow a normal distribution function. The contribution of structural effects to the variability of composite and minicomposite strength under strain-controlled loading is analyzed. Their dependence on specimen size is related to the reproducibility of critical flaw population and structural effects. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

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34 pages, 18305 KiB

Open AccessArticle

Refining Oxide Ratios in N-A-S-H Geopolymers for Optimal Resistance to Sulphuric Acid Attack

by Chaofan Yi, Yaman Boluk and Vivek Bindiganavile

J. Compos. Sci. 2025, 9(1), 44; https://doi.org/10.3390/jcs9010044 - 17 Jan 2025

Viewed by 497

Abstract

As an alternative to Portland cement systems, geopolymers have been found to display superior acid resistance. However, at present, there exists no strategy to regulate the suitable design of mixtures. Particularly, the mechanisms underlying the effect of principal oxide ratios on the performance [...] Read more.

As an alternative to Portland cement systems, geopolymers have been found to display superior acid resistance. However, at present, there exists no strategy to regulate the suitable design of mixtures. Particularly, the mechanisms underlying the effect of principal oxide ratios on the performance of N-A-S-H geopolymers in acid-rich environments are missing. Nor is any information available on the optimal range for SiO₂/Al₂O₃, Na₂O/Al₂O₃, and H₂O/Na₂O ratios under acid attack. This study investigates N-A-S-H geopolymers incorporating varying compositional oxide ratios to assess their resistance to sulphuric acid attack. The results show that the optimal range for acid-resistant durability is a narrow band within the optimal range for workability and strength. A SiO₂/Al₂O₃ ratio of 3.4 balanced the enhanced degree of geopolymerization with an increase in the amount of permeable voids. At the same time, the Na₂O/Al₂O₃ and H₂O/Na₂O ratios should be maintained within 0.8~0.9 and 8~10, respectively. Quantitatively, for the mixture designed within these optimal oxide ranges, the associated strength loss after 84 weeks of acid exposure was only about 10~20%, whereas other mix proportions may lead to a maximum strength loss of up to ~58%. Anything higher will offset the polycondensation and instead raise the volume of permeable voids. A sensitivity analysis suggests that the acid resistance depends chiefly on the Na₂O/Al₂O₃ and H₂O/Na₂O ratios. The proposed multi-factor models predict the acid-induced neutralization efficiently, and the associated output displays a correlation with the loss in compressive strength. Full article

(This article belongs to the Special Issue Novel Cement and Concrete Materials)

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16 pages, 2864 KiB

Open AccessArticle

Evaluation of Physicochemical Properties of Cadmium Oxide (CdO)-Incorporated Indium–Tin Oxide (ITO) Nanoparticles for Photocatalysis

by Habtamu Fekadu Etefa and Francis Birhanu Dejene

J. Compos. Sci. 2025, 9(1), 43; https://doi.org/10.3390/jcs9010043 - 16 Jan 2025

Viewed by 435

Abstract

This study investigates the structural, optical, and photocatalytic properties of cadmium oxide (CdO) nanoparticles (NPs) and indium–tin oxide (ITO)-doped CdO NPs. The synthesis of CdO NPs and ITO NPs was accomplished through the co-precipitation method. Scanning electron microscopy (SEM) analysis indicates that pure [...] Read more.

This study investigates the structural, optical, and photocatalytic properties of cadmium oxide (CdO) nanoparticles (NPs) and indium–tin oxide (ITO)-doped CdO NPs. The synthesis of CdO NPs and ITO NPs was accomplished through the co-precipitation method. Scanning electron microscopy (SEM) analysis indicates that pure CdO NPs exhibit agglomerated structures, whereas ITO doping introduces porosity and roughness, thereby improving particle dispersion and facilitating electron transport. Energy dispersive spectroscopy (EDS) corroborates the successful incorporation of tin (Sn) and indium (In) within indium–tin oxide (ITO)-doped cadmium oxide (CdO) nanoparticles (NPs) in addition to cadmium (Cd) and oxygen (O). X-ray diffraction (XRD) analysis demonstrates that an increase in ITO doping results in a reduction of the crystallite size, decreasing from 23.43 nm for pure CdO to 18.42 nm at a 10% doping concentration, which can be attributed to lattice distortion. Simultaneously, the band gap exhibits a narrowing from 2.92 eV to 2.52 eV, achieving an optimal value at 10% ITO doping before experiencing a slight increase at higher doping concentrations. This tuneable band gap improves light absorption, which is crucial for photocatalysis. The photocatalytic degradation of rhodamine B (RhB) highlights the superior efficiency of ITO-doped CdO nanoparticles, achieving a remarkable 94.68% degradation under sunlight within 120 min, up 81.01%, significantly surpassing the performance of pure CdO. The optimal RhB concentration for achieving maximum degradation was determined to be 5 mg/L. This enhanced catalytic activity demonstrates the effectiveness of ITO-doped CdO NPs under both UV and visible light, showcasing their potential for efficient pollutant degradation in sunlight-driven applications. Full article

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34 pages, 15553 KiB

Open AccessReview

Advances in Conductive Polymer-Based Flexible Electronics for Multifunctional Applications

by Md. Abdus Shahid, Md. Mostafizur Rahman, Md. Tanvir Hossain, Imam Hossain, Md. Sohan Sheikh, Md. Sunjidur Rahman, Nasir Uddin, Scott W. Donne and Md. Ikram Ul Hoque

J. Compos. Sci. 2025, 9(1), 42; https://doi.org/10.3390/jcs9010042 - 16 Jan 2025

Viewed by 1290

Abstract

The rapid developments in conductive polymers with flexible electronics over the past years have generated noteworthy attention among researchers and entrepreneurs. Conductive polymers have the distinctive capacity to conduct electricity while still maintaining the lightweight, flexible, and versatile characteristics of polymers. They are [...] Read more.

The rapid developments in conductive polymers with flexible electronics over the past years have generated noteworthy attention among researchers and entrepreneurs. Conductive polymers have the distinctive capacity to conduct electricity while still maintaining the lightweight, flexible, and versatile characteristics of polymers. They are crucial for the creation of flexible electronics or gadgets that can stretch, bend, and adapt to different surfaces have sparked momentous interest in electronics, energy storage, sensors, smart textiles, and biomedical applications. This review article offers a comprehensive overview of recent advancements in conductive polymers over the last 15 years, including a bibliometric analysis. The properties of conductive polymers are summarized. Additionally, the fabrication processes of conductive polymer-based materials are discussed, including vacuum filtering, hydrothermal synthesis, spray coating, electrospinning, in situ polymerization, and electrochemical polymerization. The techniques have been presented along with their advantages and limitations. The multifunctional applications of conductive polymers are also discussed, including their roles in energy storage and conversion (e.g., supercapacitors, lithium-ion batteries (LIBs), and sodium-ion batteries (SIBs)), as well as in organic light-emitting diodes (OLEDs), organic solar cells (OSCs), conductive textiles, healthcare monitoring, and sensors. Future scope and associated challenges have also been mentioned for further development in this field. Full article

(This article belongs to the Special Issue Composite Materials Containing Conjugated and Conductive Polymers)

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22 pages, 6292 KiB

Open AccessReview

Review of Bioinspired Composites for Thermal Energy Storage: Preparation, Microstructures and Properties

by Min Yu, Mengyuan Wang, Changhao Xu, Wei Zhong, Haoqi Wu, Peng Lei, Zeya Huang, Renli Fu, Francesco Gucci and Dou Zhang

J. Compos. Sci. 2025, 9(1), 41; https://doi.org/10.3390/jcs9010041 - 15 Jan 2025

Viewed by 488

Abstract

Bioinspired composites for thermal energy storage have gained much attention all over the world. Bioinspired structures have several advantages as the skeleton for preparing thermal energy storage materials, including preventing leakage and improving thermal conductivity. Phase change materials (PCMs) play an important role [...] Read more.

Bioinspired composites for thermal energy storage have gained much attention all over the world. Bioinspired structures have several advantages as the skeleton for preparing thermal energy storage materials, including preventing leakage and improving thermal conductivity. Phase change materials (PCMs) play an important role in the development of energy storage materials because of their stable chemical/thermal properties and high latent heat storage capacity. However, their applications have been compromised, owing to low thermal conductivity and leakage. The plant-derived scaffolds (i.e., wood-derived SiC/Carbon) in the composites can not only provide higher thermal conductivity but also prevent leakage. In this paper, we review recent progress in the preparation, microstructures, properties and applications of bioinspired composites for thermal energy storage. Two methods are generally used for producing bioinspired composites, including the direct introduction of biomass-derived templates and the imitation of biological structures templates. Some of the key technologies for introducing PCMs into templates involves melting, vacuum impregnation, physical mixing, etc. Continuous and orderly channels inside the skeleton can improve the overall thermal conductivity, and the thermal conductivity of composites with biomass-derived, porous, silicon carbide skeleton can reach as high as 116 W/m*K. In addition, the tightly aligned microporous structure can cover the PCM well, resulting in good leakage resistance after up to 2500 hot and cold cycles. Currently, bioinspired composites for thermal energy storage hold the greatest promise for large-scale applications in the fields of building energy conservation and solar energy conversion/storage. This review provides guidance on the preparation methods, performance improvements and applications for the future research strategies of bioinspired composites for thermal energy storage. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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17 pages, 3219 KiB

Open AccessArticle

The Influence of Architecture on the Tensile and Flexural Properties of Single-Polymer Composites

by Yogeshvaran R. Nagarajan, Farukh Farukh and Karthikeyan Kandan

J. Compos. Sci. 2025, 9(1), 40; https://doi.org/10.3390/jcs9010040 - 15 Jan 2025

Viewed by 356

Abstract

This study investigates the tensile and flexural properties of self-reinforced polylactic acid (SrPLA) and poly(ethylene terephthalate) (SrPET) for prosthetic socket applications. These self-reinforced polymer (srP) composites utilize both a matrix and reinforcement made from the same material, resulting in an optimal matrix–interface bond [...] Read more.

This study investigates the tensile and flexural properties of self-reinforced polylactic acid (SrPLA) and poly(ethylene terephthalate) (SrPET) for prosthetic socket applications. These self-reinforced polymer (srP) composites utilize both a matrix and reinforcement made from the same material, resulting in an optimal matrix–interface bond that significantly enhances mechanical properties compared to traditional bulk polymers and composites. Prosthetic sockets serve as a critical interface between an amputee’s residuum and the prosthetic components, such as pylons and feet. Conventional socket materials, including monolithic high-density polyethylene and polypropylene, as well as advanced fillers reinforced with thermoset resins, often fall short in strength or affordability, particularly for amputees in low- to middle-income countries. In this study, we employed srP composites with various architectural stitch densities, aiming to achieve superior material properties. The results demonstrate that these materials exhibit higher strength and strain capabilities than many existing prosthetic materials. Notably, the low-density srPET composites achieved a tensile strength of 85.11 MPa and a strain of 19.7%, while high-density srPLA exhibited a failure strength of 36.65 MPa and a strain of 1.4%. Additionally, our findings reveal that the stiffness of both srPLA and srPET increases as the density of the reinforcement decreases. Overall, this study suggests that srP composites represent a viable and sustainable alternative for the manufacturing of prosthetic sockets, offering both enhanced performance and cost-effectiveness. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

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19 pages, 5487 KiB

Open AccessArticle

A Comparative Environmental and Economic Analysis of Carbon Fiber-Reinforced Polymer Recycling Processes Using Life Cycle Assessment and Life Cycle Costing

by Christina Vogiantzi and Konstantinos Tserpes

J. Compos. Sci. 2025, 9(1), 39; https://doi.org/10.3390/jcs9010039 - 15 Jan 2025

Viewed by 445

Abstract

The recycling of carbon-fiber reinforced polymers (CFRPs) presents significant challenges due to their thermosetting matrix, which complicates end-of-life management and often results in energy-intensive disposal or significant waste accumulation. Despite advancements in recycling methods, knowledge gaps remain regarding their sustainability and economic viability. [...] Read more.

The recycling of carbon-fiber reinforced polymers (CFRPs) presents significant challenges due to their thermosetting matrix, which complicates end-of-life management and often results in energy-intensive disposal or significant waste accumulation. Despite advancements in recycling methods, knowledge gaps remain regarding their sustainability and economic viability. This study undertakes a comprehensive Life Cycle Assessment and Environmental Life Cycle Costing analysis of four key recycling techniques: mechanical recycling, pyrolysis, solvolysis, and high-voltage fragmentation (HVF). By using the SimaPro software, this study identifies mechanical recycling and HVF as the most sustainable options, with the lowest cumulative energy demand (CED) of 5.82 MJ/kg and 4.97 MJ/kg and global warming potential (GWP) of 0.218 kg CO₂eq and 0.0796 kg CO₂eq, respectively. In contrast, pyrolysis imposes the highest environmental burdens, requiring 66.3 MJ/kg and emitting 2.84 kg CO₂eq. Subcritical solvolysis shows more balanced environmental impacts compared to its supercritical counterpart. Cost analysis reveals that for mechanical recycling and pyrolysis, material costs are negligible or zero. In contrast, solvolysis and HVF incur material costs primarily due to the need for deionized water. Regarding energy costs, pyrolysis stands out as the most expensive method due to its high energy demands, followed closely by solvolysis with supercritical water. Full article

(This article belongs to the Special Issue Advances in Composite Carbon Fibers)

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14 pages, 3837 KiB

Open AccessArticle

Evaluation of Mechanical Properties of Sabai Grass (Eulaliopsis binata) Fibers and Epoxy Resin Composite Laminates Using Fly Ash as Filler Material

by Shambhu Kumar, Ratnakar Das and Sambit Kumar Parida

J. Compos. Sci. 2025, 9(1), 38; https://doi.org/10.3390/jcs9010038 - 14 Jan 2025

Viewed by 506

Abstract

The integration of sabai grass fibers and fly ash in epoxy resin combines the strengths of both materials for developing a tailor-made composite laminate that balances performance, sustainability, and cost-efficiency. This innovative blend of natural fibers and industrial waste promotes environmental conservation. The [...] Read more.

The integration of sabai grass fibers and fly ash in epoxy resin combines the strengths of both materials for developing a tailor-made composite laminate that balances performance, sustainability, and cost-efficiency. This innovative blend of natural fibers and industrial waste promotes environmental conservation. The laminates produced could also be used in diverse industrial and structural applications. This study investigated the mechanical properties of composite laminates reinforced with sabai grass fibers, fly ash filler, and epoxy resin as the matrix. In this work, the hand lay-up method was used to fabricate composites with two stacking configurations ((0°/0°/0°/0°) and (0°/90°/90°/0°)) and filler contents of 1.5 wt.%, 3 wt.%, and 5 wt.%. Various weight fractions of fly ash filler and sabai grass fiber were integrated into the epoxy resin to evaluate their impact on tensile strength, flexural strength, and hardness. The experimental results indicate that adding fly ash significantly improves the composite’s hardness to 27 HV in the composites containing 5 wt.% filler, while sabai grass fibers contribute to enhanced tensile strength and flexural strength. The composites with (0°/0°/0°/0°) fibers and 5 wt.% filler showed a higher tensile strength of 63.5 MPa and flexural strength of 118.5 MPa. The fractured sample was analyzed with the help of FESEM images. The XRD analysis confirmed the presence of fly ash components suitable for forming a bond with epoxy. EDX was conducted to determine the elemental composition of the fly ash. FTIR analysis verified the removal of impurities such as dust, dirt, and lignin from the fiber surface following NaOH treatment. Full article

(This article belongs to the Section Composites Modelling and Characterization)

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27 pages, 6639 KiB

Open AccessArticle

Comprehensive Analysis of Wear, Friction, and Thermal Resistance in PVDF/Nanoclay Composites Using Taguchi Methodology for Enhanced Tribological Performance

by Pavan Hiremath, R. C. Shivamurthy, Giridhar B. Kamath and Nithesh Naik

J. Compos. Sci. 2025, 9(1), 37; https://doi.org/10.3390/jcs9010037 - 14 Jan 2025

Viewed by 362

Abstract

This study discusses the tribological characteristics of Polyvinylidene Fluoride (PVDF)/nanoclay composites, focusing on the effects of nanoclay content (0, 1, 2 and 3 wt.%), load, sliding speed, and sliding distance on the wear rate, friction coefficient, specific wear rate, and temperature. A Taguchi [...] Read more.

This study discusses the tribological characteristics of Polyvinylidene Fluoride (PVDF)/nanoclay composites, focusing on the effects of nanoclay content (0, 1, 2 and 3 wt.%), load, sliding speed, and sliding distance on the wear rate, friction coefficient, specific wear rate, and temperature. A Taguchi Design of Experiments technique was applied to optimize and assess these aspects. The results demonstrated that nanoclay addition considerably improved the wear resistance and frictional stability of the PVDF composites. Specifically, a nanoclay concentration of 3 wt.% gave the lowest wear rate (0.05 mg/m) with a 10 N load and 100 m sliding distance, lowering wear by roughly 23% compared to unreinforced PVDF. The friction coefficient was similarly lowered by 12% with 3 wt.% nanoclay, reaching a value of 0.38 at the highest load of 40 N. Interaction effects demonstrate that load and sliding distance are key elements impacting wear performance, with large loads and long distances virtually tripling the wear rate. ANOVA results quantify nanoclay’s contribution to a wear rate reduction of 51.29%, whereas load and sliding distance contributed 22.47% and 16.98%, respectively. Temperature increases due to frictional heating reached 10 °C under rigorous test conditions, although nanoclay treatment decreased this increase by an average of 15%. Characterization by XRD and FTIR verified the nanoclay dispersion inside the PVDF matrix, whereas the SEM images demonstrated smoother surfaces and fewer wear tracks in the nanoclay-reinforced samples. These findings illustrate the efficiency of nanoclay in increasing the wear resistance of PVDF, making these composites appropriate for high-performance applications. This research provides useful insights into enhancing PVDF/nanoclay composites, with possible uses in situations that demand endurance and thermal stability. Full article

(This article belongs to the Section Polymer Composites)

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14 pages, 3519 KiB

Open AccessArticle

Kinetic, Isothermal and Thermodynamic Study on the Removal of Hexavalent Chromium with Biocomposites (Cellulose–PLA)

by Candelaria Tejada-Tovar, Ángel Villabona-Ortiz and Rodrigo Ortega-Toro

J. Compos. Sci. 2025, 9(1), 36; https://doi.org/10.3390/jcs9010036 - 14 Jan 2025

Viewed by 460

Abstract

Currently, water is being polluted via various anthropogenic activities, resulting in wastewater contaminated with multiple pollutants, including heavy metals. Hexavalent chromium is a toxic heavy metal that poses significant health risks upon exposure. Biocomposites are materials that are partially composed of organic substances [...] Read more.

Currently, water is being polluted via various anthropogenic activities, resulting in wastewater contaminated with multiple pollutants, including heavy metals. Hexavalent chromium is a toxic heavy metal that poses significant health risks upon exposure. Biocomposites are materials that are partially composed of organic substances that enhance different properties of a composite. The aim of this study was to evaluate the kinetic, isothermal, and thermodynamic behaviour of a cellulose-based biocomposite with polylactic acid (PLA) for the removal of Cr (VI) from synthetic water. The results indicated that the Freundlich and Elovich models provided the best fit for the isothermal and kinetic data, with R² values of 0.671 and 0.973, respectively, suggesting that the adsorption process was chemical in nature and occurred on a heterogeneous, multilayer surface. Additionally, the thermodynamic analysis revealed that the adsorption process was exothermic, irreversible, and non-spontaneous. This study presents an innovative approach to the removal of metal ions using a cellulose–PLA biocomposite for wastewater treatment, offering kinetic, isothermal, and thermodynamic data applicable to the adsorption of other heavy metals. Full article

(This article belongs to the Special Issue Sustainable Biocomposites, Volume II)

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20 pages, 2567 KiB

Open AccessReview

Fiber Metal Laminates: The Role of the Metal Surface and Sustainability Aspects

by Mariateresa Caggiano, Maria Rosaria Saffioti and Giovanna Rotella

J. Compos. Sci. 2025, 9(1), 35; https://doi.org/10.3390/jcs9010035 - 13 Jan 2025

Viewed by 633

Abstract

Fiber Metal Laminates (FMLs), a class of hybrid materials combining the benefits of metals and composites, have emerged as promising lightweight structural materials. Consequently, research interest in FML production technologies is growing. According to a thorough analysis of the state of the art, [...] Read more.

Fiber Metal Laminates (FMLs), a class of hybrid materials combining the benefits of metals and composites, have emerged as promising lightweight structural materials. Consequently, research interest in FML production technologies is growing. According to a thorough analysis of the state of the art, the effectiveness of surface treatments in influencing the bond strength, formability, and durability of components during FML manufacturing still needs to be better understood. This paper compares several functionalization strategies to optimize the surface characteristics that lead to superior FML quality: burnishing, laser texturing, sandblasting, and chemical etching. Each method will be appropriately set up to alter the surface’s initial characteristics and, consequently, the adhesion performance for the subsequent stages. Moreover, sustainability considerations are also considered during surface functionalization processes. This study aims to assess and optimize these techniques for reduced environmental impact, considering energy efficiency and waste reduction. By integrating sustainable practices into FML manufacturing, this research seeks to enhance the overall environmental profile of these advanced materials. Full article

(This article belongs to the Section Fiber Composites)

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11 pages, 3641 KiB

Open AccessArticle

Effective CdS:(Ce, Ga) Nanoparticles for Photocatalytic H₂ Production Under Artificial Solar Light Exposer

by Pedda Thimmula Poojitha, Radhalayam Dhanalakshmi, Mohammad Rezaul Karim, Sung Jin An, Kummara Madhusudana Rao, Siva Pratap Reddy Mallem and Young Lae Kim

J. Compos. Sci. 2025, 9(1), 34; https://doi.org/10.3390/jcs9010034 - 13 Jan 2025

Viewed by 411

Abstract

To encounter the burgeoning energy demands of the future, it is imperative to focus on the progress of innovative and profitable techniques for hydrogen (H₂) evolution, coupled with an enriched stability of photocatalysts. In this work, we have effectually prepared CdS, [...] Read more.

To encounter the burgeoning energy demands of the future, it is imperative to focus on the progress of innovative and profitable techniques for hydrogen (H₂) evolution, coupled with an enriched stability of photocatalysts. In this work, we have effectually prepared CdS, CdS:Ce, and CdS:(Ce, Ga) nanoparticles through a chemical refluxing method at 120 °C. Comprehensive structural analysis confirmed the effectual incorporation of Ce and Ga ions in the place of Cd²⁺ in a CdS matrix. Morphology analysis indicates that the prepared samples are irregularly shaped nanoparticles. Chemical analysis confirmed that the Ce and Ga ions incorporated in the Cd site occurred with 3+ and 4+ valence states. All the samples were assessed for H₂ production through water splitting via artificial solar light irradiation. Amid all the samples, CdS:(Ce, Ga) nanoparticles portrayed a giant H₂ evolution efficacy (3012 µmol h⁻¹g⁻¹) in 300 min, which is 13.9 times larger than that of the bar CdS sample. Thus, we firmly propose that CdS:(Ce, Ga) samples are authentic and potent candidates for efficient photocatalytic H₂ production in sterile environments. Full article

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21 pages, 4744 KiB

Open AccessReview

Three-Dimensional Printing of Polymer Composites: Manufacturing and Mechanics

by Ryan Bernardy and Yingtao Liu

J. Compos. Sci. 2025, 9(1), 33; https://doi.org/10.3390/jcs9010033 - 12 Jan 2025

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Abstract

Polymers have been heavily used in manufacturing for decades, and with their use, improvements in the desired materials via composite materials utilizing a polymer matrix have been commonplace. Naturally, the increase in polymer additive manufacturing has come with an increase in interest in [...] Read more.

Polymers have been heavily used in manufacturing for decades, and with their use, improvements in the desired materials via composite materials utilizing a polymer matrix have been commonplace. Naturally, the increase in polymer additive manufacturing has come with an increase in interest in additively manufacturing polymer composites. This paper primarily covers the fused deposition modeling (FDM) method, ultraviolet (UV)-cured resin methods, multiple resin printing, and embedded sensors associated with additive manufacturing. In particular, the manufacturing and subsequent effect on material properties compared to unreinforced and unmodified 3D-printed polymers, the tradeoffs required in doing so, and the mechanisms behind these effects are discussed. The manufacturing methodology used or developed and the mechanisms behind these selections are discussed along with insights that could be gathered from material property effects seen across different studies. The mechanisms discussed also focus on the mechanisms between the different materials comprising the composite produced. Full article

(This article belongs to the Special Issue Additive Manufacturing of Advanced Composites, 2nd Edition)

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12 pages, 3136 KiB

Open AccessArticle

Magnetic and Dielectric Properties of Cobalt and Zirconium Co-Doped Iron Oxide Nanoparticles via the Hydrothermal Synthesis Approach

by Saba Yaqoob, Zulfiqar Ali and Alberto D’Amore

J. Compos. Sci. 2025, 9(1), 32; https://doi.org/10.3390/jcs9010032 - 11 Jan 2025

Viewed by 379

Abstract

This study investigates the magnetic and dielectric properties of cobalt–zirconium co-doped iron oxide nanoparticles synthesized via the hydrothermal method. The synthesis was conducted at 150 °C, with reaction times of 4, 6, 8, 10, and 12 h. Co-doping with cobalt and zirconium significantly [...] Read more.

This study investigates the magnetic and dielectric properties of cobalt–zirconium co-doped iron oxide nanoparticles synthesized via the hydrothermal method. The synthesis was conducted at 150 °C, with reaction times of 4, 6, 8, 10, and 12 h. Co-doping with cobalt and zirconium significantly influenced the magnetic phase formation of iron oxide. Magnetic properties were characterized using a Vibrating Sample Magnetometer (VSM), revealing ferromagnetic behavior with a maximum saturation magnetization of 45 emu/g for the 8 h sample. The dielectric properties were analyzed through impedance spectroscopy across a wide frequency range, and the results were interpreted using Maxwell–Wagner’s model and Koop’s theory. The dielectric constant reached its maximum value of approximately 58 at a logarithmic frequency of 1.5 Hz for the sample synthesized for 8 h. This study highlights the importance of synthesis time in optimizing both the magnetic and dielectric properties of (Co, Zr) co-doped iron oxide nanoparticles. Full article

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21 pages, 6651 KiB

Open AccessArticle

Electrospun Aligned Gelatin/Chitosan Nanofibrous Membranes for a Better Culture of Mesothelial Cells

by Hao-Hsi Kao, Darshan Tagadur Govindaraju, Banendu Sunder Dash and Jyh-Ping Chen

J. Compos. Sci. 2025, 9(1), 31; https://doi.org/10.3390/jcs9010031 - 10 Jan 2025

Viewed by 693

Abstract

The delivery of mesothelial cells by nanofibrous membranes (NFMs) can repair a damaged peritoneal mesothelium and enhance peritoneal healing in patients with chronic renal failure. On the other hand, the orientation of the nanofibers in NFMs may affect cell attachment, proliferation, and the [...] Read more.

The delivery of mesothelial cells by nanofibrous membranes (NFMs) can repair a damaged peritoneal mesothelium and enhance peritoneal healing in patients with chronic renal failure. On the other hand, the orientation of the nanofibers in NFMs may affect cell attachment, proliferation, and the phenotype of mesothelial cells in the nanostructured scaffold. We prepare composite gelatin/chitosan NFMs with aligned or random fiber orientations by electrospinning. We cross-link the nanofibers to maintain the fiber orientation during in vitro cell culture. We then study the cellular response of attached mesothelial cells to fiber orientation in the scaffold. From in vitro cell culture with rat mesothelial cells, the prepared NFMs show high biocompatibility to support cellular growth, regardless of fiber orientation. However, the alignment of electrospun nanofibers in a well-defined geometry can promote cell adhesion and proliferation rates with directional cell organization. The anisotropic arrangement of mesothelial cells in the aligned NFM also coincides with the phenotypic maintenance of the attached mesothelial cells, with biophysical cues provided by the aligned nanofibers. The aligned NFMs may find applications in tissue engineering of a damaged mesothelium layer or in other regenerative therapies where cellular alignment is critical for neo-tissue regeneration. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

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33 pages, 19633 KiB

Open AccessFeature PaperArticle

Evaluation of Antimicrobial Activity, Hemostatic Efficacy, Blood Coagulation Dynamics, and DNA Damage of Linen–Copper Composite Materials

by Zdzisława Mrozińska, Małgorzata Świerczyńska, Michał Juszczak, Katarzyna Woźniak and Marcin H. Kudzin

J. Compos. Sci. 2025, 9(1), 30; https://doi.org/10.3390/jcs9010030 - 10 Jan 2025

Viewed by 348

Abstract

This research examined the biochemical and microbiological characteristics of linen–copper (LI-Cu) composite materials, which were synthesized using magnetronsputtering techniques. The LI-Cu composites underwent comprehensive physicochemical and biological analyses. Physicochemical evaluations included elemental analysis (C, O, Cu), microscopic examination, and assessments of surface properties [...] Read more.

This research examined the biochemical and microbiological characteristics of linen–copper (LI-Cu) composite materials, which were synthesized using magnetronsputtering techniques. The LI-Cu composites underwent comprehensive physicochemical and biological analyses. Physicochemical evaluations included elemental analysis (C, O, Cu), microscopic examination, and assessments of surface properties such as specific surface area and total pore volume. Biological evaluations encompassed microbiological tests and biochemical–hematological assessments, including the activated partial thromboplastin time (aPTT) and prothrombin time (PT). We determined the effect of LI-Cu materials on the viability and DNA damage in peripheral blood mononuclear (PBM) cells. Moreover, we studied the interactions of LI-Cu materials with plasmid DNA using a plasmid relaxation assay. The antimicrobial activity of LI-Cu composites was assessed using methodologies consistent with the EN ISO 20645:2006 and EN 14119:2005 standards. Specimens of the tested material were placed on inoculated agar plates containing representative microorganisms, and the extent of growth inhibition zones was measured. The results demonstrated that the modified materials exhibited antimicrobial activity against representative strains of Gram-positive and Gram-negative bacteria, as well as fungi. The results showed the cyto- and genotoxic properties of LI-Cu against PBM cells in a time- and power-dependent manner. Furthermore, the LI-Cu composite exhibited the potential for direct interaction with plasmid DNA. Full article

(This article belongs to the Special Issue Metal Composites, Volume II)

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17 pages, 9648 KiB

Open AccessArticle

Effects of the Rate Dependency of a Matrix Material on the Tensile Response of Plain Weave Carbon Fabric Reinforced Epoxy Composites

by Taeseong Choi and Wooseok Ji

J. Compos. Sci. 2025, 9(1), 29; https://doi.org/10.3390/jcs9010029 - 9 Jan 2025

Viewed by 395

Abstract

Textile composites are extensively used in structures subjected to both static and dynamic loads. However, research on how loading rates influence performance remains limited. A better understanding of how the rate dependency of matrix materials affects the mechanical behavior of textile composites could [...] Read more.

Textile composites are extensively used in structures subjected to both static and dynamic loads. However, research on how loading rates influence performance remains limited. A better understanding of how the rate dependency of matrix materials affects the mechanical behavior of textile composites could facilitate more accurate performance predictions and the efficient selection of components based on loading rates. This study investigates the effect of the rate dependency of epoxy on the overall rate dependency of a plain weave carbon fabric-reinforced epoxy composite. Specimens were prepared using only epoxy resin, and tensile tests were conducted at four loading rates (5 mm/min, 50 mm/min, 200 mm/min, and 800 mm/min) to evaluate changes in the tensile properties of epoxy with varying loading rates. Composite specimens were fabricated using the same epoxy, and tensile tests were performed under identical conditions. The results demonstrated that both materials became more brittle at higher loading rates while their stiffness remained largely unaffected. Furthermore, the failure process of the composite at different loading rates was analyzed through micro-scale finite element analysis. The analysis revealed that the onset of failure in textile composites shifted owing to the rate-dependent brittleness of epoxy. To mitigate the high computational cost of explicit simulations accounting for time dependency, a modified Johnson–Cook model and an acceleration model were newly developed and incorporated into the analysis. Full article

(This article belongs to the Section Composites Modelling and Characterization)

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16 pages, 7152 KiB

Open AccessArticle

Micro-Scale Numerical Simulation for Residual Strength of CFRP After Cyclic Tensile or Out-of-Plane Shear Loadings Fatigue

by Takumi Sekino, Natsuko Kudo and Jun Koyanagi

J. Compos. Sci. 2025, 9(1), 28; https://doi.org/10.3390/jcs9010028 - 8 Jan 2025

Viewed by 524

Abstract

In this study, micro-scale numerical simulations were performed to evaluate the residual strength of carbon fiber-reinforced polymers (CFRPs) subjected to cyclic transverse and out-of-plane shear loading fatigue. The simulations utilized a finite element method, incorporating an entropy-based damage criterion for the matrix resin. [...] Read more.

In this study, micro-scale numerical simulations were performed to evaluate the residual strength of carbon fiber-reinforced polymers (CFRPs) subjected to cyclic transverse and out-of-plane shear loading fatigue. The simulations utilized a finite element method, incorporating an entropy-based damage criterion for the matrix resin. This method aimed to link entropy generation to strength degradation, with the parameter

α_{o} (s)

determined as a function of entropy. Cyclic tensile and shear analyses were conducted to correlate residual strength with entropy accumulation, establishing a linear relationship for

α_{o} (s)

. The results demonstrated meso-scale strength degradation based on micro-scale numerical simulations. Material constants for the epoxy resin matrix were determined through creep and tensile tests, and a generalized Maxwell model with 15 elements was used to represent viscoelastic behavior. Numerical simulations employed the Abaqus/Standard 2020 software, with the epoxy resin matrix behavior implemented via a UMAT subroutine. The analysis revealed a linear relationship between entropy and residual strength for both cyclic tensile and out-of-plane shear loading. This approach enhances experimental insights with numerical predictions, offering a comprehensive understanding of CFRP strength degradation under fatigue loading. This study represents the first numerical approach to link the entropy of the matrix resin at the micro-scale with macro-scale residual strength in CFRP, providing a novel and comprehensive framework for understanding and predicting strength degradation under cyclic loading. Full article

(This article belongs to the Section Polymer Composites)

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16 pages, 3278 KiB

Open AccessArticle

Masking Ability and Translucency of Direct Gingiva-Colored Resin-Based Restorative Materials

by Thanasak Rakmanee, Seelassaya Leelaponglit, Chadinthorn Janyajirawong, Apisada Bannagijsophon, Kamon Budsaba and Awiruth Klaisiri

J. Compos. Sci. 2025, 9(1), 27; https://doi.org/10.3390/jcs9010027 - 8 Jan 2025

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Abstract

This study aimed to investigate the effects of shade, thickness, and the application of an opaquer on the masking ability and translucency of direct gingiva-colored giomer. Five shades of giomer, namely Gum-Light-Pink, Gum-Dark-Pink, Gum-Brown, Gum-Violet, and Gum-Orange, were evaluated at thicknesses of 0.5, [...] Read more.

This study aimed to investigate the effects of shade, thickness, and the application of an opaquer on the masking ability and translucency of direct gingiva-colored giomer. Five shades of giomer, namely Gum-Light-Pink, Gum-Dark-Pink, Gum-Brown, Gum-Violet, and Gum-Orange, were evaluated at thicknesses of 0.5, 1.0, 1.5, and 2.0 mm. Color measurements were obtained using a spectrophotometer against white, black, and giomer backgrounds. The results were analyzed using the CIEDE2000 color-difference formula and interpreted based on the 50:50% thresholds for excellent perceptibility (ΔE₀₀ < 1.1) and acceptability (ΔE₀₀ < 2.8). Measurements were repeated after applying an opaquer. Acceptable masking ability was achieved at 0.5 mm for all shades. Excellent masking ability was achieved at 1.5 mm for all shades, except Gum-Brown, which required 1.0 mm. The opaquer increased masking ability in all specimens. Translucency decreased as thickness increased (p < 0.0001). Gum-Brown and Gum-Light-Pink, as well as Gum-Orange and Gum-Dark-Pink, demonstrated similar translucency at 0.5, 1.0, and 1.5 mm (p > 0.05). After applying the opaquer, there were no statistically significant differences in translucency among shades at 1.5 mm and 2.0 mm (p > 0.05). In conclusion, increasing thickness improved masking ability but reduced translucency of gingiva-colored material. The opaquer further enhanced masking ability and reduced translucency. The clinical significance of these results are that gingiva-colored restorations mask discolored tooth defects in the pink aesthetic area with minimal 0.5 mm tooth preparation, achieving acceptable results. The addition of an opaquer enhances masking ability for excellent outcomes. Full article

(This article belongs to the Special Issue Innovations in Direct and Indirect Dental Composite Restorations)

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10 pages, 2327 KiB

Open AccessArticle

Cure Efficiency and Biocompatibility of an Iron-Based Coordination Complex as a Photoinitiator for Dental 3D-Printed Resins

by Sharanya Singh, Mateus Garcia Rocha, Mario Alexandre Coelho Sinhoreti, Alexandre Carneiro Silvino and Dayane Oliveira

J. Compos. Sci. 2025, 9(1), 26; https://doi.org/10.3390/jcs9010026 - 8 Jan 2025

Viewed by 391

Abstract

Objective: The aim of this study was to evaluate the cure efficiency and biocompatibility of a novel iron-based coordination complex used as a photoinitiator in comparison to conventional ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L) and camphorquinone (CQ) as photoinitiators in dental 3D-printed resins. Materials and [...] Read more.

Objective: The aim of this study was to evaluate the cure efficiency and biocompatibility of a novel iron-based coordination complex used as a photoinitiator in comparison to conventional ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L) and camphorquinone (CQ) as photoinitiators in dental 3D-printed resins. Materials and Methods: Experimental dental resin formulations were prepared by blending 1:1 ratio of Bis-GMA and TEGDMA, to which 0.2 wt% of either the iron-based coordination complex or CQ were added, along with 0.2 wt% EDAB and 0.4 wt% IOD, and the TPO-L. The degree of conversion (DC) was measured using Fourier transform infrared spectroscopy (FTIR). Biocompatibility was assessed by evaluating the viability of L929 fibroblast-like cells using the MTT assay 24 h post-exposure. Statistical analyses included a two-way ANOVA followed by Tukey’s test for post hoc comparisons, with significance at p < 0.05. Results: The degree of conversion for the iron-based coordination complex (84.54% ± 1.69%) was significantly higher than that for the TPO-L (78.77% ± 1.25%) and CQ-based resins (73.21% ± 0.47%) (p < 0.001). The iron-based coordination complex and TPO-L resins exhibited significantly higher conversion than CQ-based resins (p < 0.001). Regarding biocompatibility, the cell viability test revealed that the iron-based coordination complex demonstrated the highest cell viability at 86.5% ± 10.24%, followed by TPO-L with 80.03% ± 11.07%. CQ showed the lowest cell viability of 51.29% ± 8.44% (p < 0.05). Tukey’s test confirmed significant differences between CQ and other photointiators (p < 0.05), while no significant difference was found between TPO-L and the iron-based coordination complex. Conclusions: This study introduces a novel iron-based coordination complex photoinitiator that demonstrates enhanced cure efficiency and comparable biocompatibility to TPO-L, while significantly reducing the cytotoxicity associated with CQ. Its longer absorption wavelength supports deeper layer curing, making it a promising alternative for dental 3D printing, particularly in bioactive scaffold applications requiring minimized cytotoxicity. Full article

(This article belongs to the Section Biocomposites)

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17 pages, 8908 KiB

Open AccessArticle

Carbon Nanoparticle-Loaded PLA Nanofibers via Electrospinning for Food Packaging

by Pietro Di Matteo, Francesco Barbero, Enrique Giménez-Torres, Ivana Fenoglio, Elena Destro, Valentina Brunella and Águeda Sonseca Olalla

J. Compos. Sci. 2025, 9(1), 25; https://doi.org/10.3390/jcs9010025 - 7 Jan 2025

Viewed by 488

Abstract

The development of nanocomposite materials for food packaging applications requires a precise balance of material functionality, safety, and regulatory compliance. In this work, the design, manufacturing, optimization, feasibility, and safety profile of polylactic acid (PLA) nanofibers filled with biocompatible carbon nanoparticles (CNP) and [...] Read more.

The development of nanocomposite materials for food packaging applications requires a precise balance of material functionality, safety, and regulatory compliance. In this work, the design, manufacturing, optimization, feasibility, and safety profile of polylactic acid (PLA) nanofibers filled with biocompatible carbon nanoparticles (CNP) and copper-loaded (CNP-Cu) nanoparticles by electrospinning are presented. To ensure nanoparticle compatibility with the PLA solvent system and achieve a uniform dispersion of the nanoparticles within nanofibers, dynamic light scattering analysis was employed, while the incorporation efficiency was demonstrated by building a novel UV–vis spectroscopy analytical method. Morphological analysis, performed through FE-SEM and TEM, confirmed the homogeneous distribution of CNP and CNP-Cu nanoparticles without aggregation. Migration studies in aqueous food simulants were also carried out to assess the material’s safety profile. The results showed minimal nanoparticle release, and the calculated copper migration was well within the limits set by European Commission Regulation (EU) No. 10/2011 for food contact materials. Full article

(This article belongs to the Section Fiber Composites)

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26 pages, 15675 KiB

Open AccessArticle

Enhancing the Toughness of Composite Cold-Formed Steel Beams with ECC and Different Stiffener Arrangements and Shapes

by Mahmoud T. Nawar, Ola A. Silem, Ishac Ibrahim, Hassan M. Maaly and Yasser E. Ibrahim

J. Compos. Sci. 2025, 9(1), 24; https://doi.org/10.3390/jcs9010024 - 7 Jan 2025

Viewed by 382

Abstract

This study investigates the toughness and load capacity of various innovative beam configurations of cold-formed steel beams (CFSB) using both ordinary concrete slabs and engineered cementitious composite (ECC) slabs. A finite element analysis with ABAQUS 20 was conducted on double-channel, sigma, G, and [...] Read more.

This study investigates the toughness and load capacity of various innovative beam configurations of cold-formed steel beams (CFSB) using both ordinary concrete slabs and engineered cementitious composite (ECC) slabs. A finite element analysis with ABAQUS 20 was conducted on double-channel, sigma, G, and omega sections, both with and without inverted lips, as well as the effects of L, channel, and trapezoidal stiffeners and length-to-depth ratios. The double-omega section with ordinary concrete achieved the highest first peak load of 365.2 kN and a toughness increase of 181.1%. Inverted lips enhanced toughness in the double-G and sigma sections, with increases of 156.9% and 158.3%, respectively. Among ECC configurations, the double-omega section with ECC3 slab reached 387.4 kN and a toughness increase of 199.5%. Thinner ordinary concrete sections (70 mm and 90 mm) negatively impacted toughness, emphasizing the need for adequate thickness. Trapezoidal stiffeners also improved toughness. These findings highlight the importance of geometrical design and material selection in optimizing CFSB performance, offering valuable insights for future design practices. Full article

(This article belongs to the Special Issue Recent Progress in Hybrid Composites)

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23 pages, 3201 KiB

Open AccessArticle

Machine Learning Approach for Prediction and Reliability Analysis of Failure Strength of U-Shaped Concrete Samples Joined with UHPC and PUC Composites

by Sadi I. Haruna, Yasser E. Ibrahim and Ibrahim Khalil Umar

J. Compos. Sci. 2025, 9(1), 23; https://doi.org/10.3390/jcs9010023 - 6 Jan 2025

Viewed by 851

Abstract

To meet the increasing demand for resilient infrastructure in seismic and high-impact areas, accurate prediction and reliability analysis of the performance of composite structures under impact loads is essential. Conventional techniques, including experimental testing and high-quality finite element simulation, require considerable time and [...] Read more.

To meet the increasing demand for resilient infrastructure in seismic and high-impact areas, accurate prediction and reliability analysis of the performance of composite structures under impact loads is essential. Conventional techniques, including experimental testing and high-quality finite element simulation, require considerable time and resources. To address these issues, this study investigated individual and hybrid models including support vector regression (SVR), Gaussian process regression (GPR), and improved eliminate particle swamp optimization hybridized artificial neural network (IEPANN) models for predicting the failure strength of composite concrete developed by combining normal concrete (NC) with ultra-high performance concrete (UHPC) and polyurethane-based polymer concrete (PUC), considering different surface treatments and subjected to various static and impact loads. An experimental dataset was utilized to train the ML models and perform the reliability analysis on the impact dataset. Key parameters included compressive strength (Cfc), flexural load of the U-shaped specimens (P), density (ρ), first crack strength (N1), and splitting tensile strength (ft). Results revealed that all the developed models had high prediction accuracy, achieving NSE values above acceptable thresholds greater than 90% across all the datasets. Statistical errors such as RMSE, MAE, and PBIAS were calculated to fall within acceptable limits. Hybrid IEPANN appeared to be the most effective model, demonstrating the highest NSE value of 0.999 and the lowest RMSE, PBIAS, and MAE values of 0.0013, 0.0018, and 0.001, respectively. The reliability analysis revealed that impact times (N1 and N2) reduced as the survival probability increased. Full article

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22 pages, 1750 KiB

Open AccessArticle

Influence of Walnut Shell Ash and Limestone Filler in Hot Mix Asphalt

by Yasir N. Kadhim, Abdulrasool Th. Abdulrasool, Anmar Dulaimi, Hugo Alexandre Silva Pinto and Luís Filipe Almeida Bernardo

J. Compos. Sci. 2025, 9(1), 22; https://doi.org/10.3390/jcs9010022 - 6 Jan 2025

Viewed by 472

Abstract

The presence of filler in asphalt concrete may improve the properties of the mixture. This study investigates the mechanical and volumetric properties of such a mixture using walnut shell ash as a filler in various replacement ratios. The mixtures were mixed with various [...] Read more.

The presence of filler in asphalt concrete may improve the properties of the mixture. This study investigates the mechanical and volumetric properties of such a mixture using walnut shell ash as a filler in various replacement ratios. The mixtures were mixed with various proportions of limestone (0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100%) in addition to WSA as a replacement filler. Tests were subsequently carried out, including tests of Marshall’s stability and flow, voids in mineral aggregates, air voids, and theoretical maximum specific gravity. The results revealed that increasing the replacement percentage resulted in a considerable improvement in the performance of the asphalt–concrete mixtures. The results revealed that the mixture with a 60% replacement ratio achieved the best Marshall stability, achieving an improvement of 15.02% compared to the conventional sample, alongside good flow properties. This improvement was accompanied by high conformity with the other physical properties of the asphalt mixture, including a 3.55% air void percentage, which is within the permissible limits for the surface layer, as well as a 21.80% increase in the percentage of voids in the mineral aggregate, which is considered an ideal value. These results paved the way for further study and adjustments to other requirements of the asphalt mixture, as there were no issues with the availability or production costs of the filler material, given the abundance of raw materials. However, it is important to note that, as is evident from the results, a complete 100% replacement led to undesirable outcomes, resulting in a 10.68% decrease in Marshall strength compared to that of the conventional sample. This decrease indicates that the mixture was unable to provide its most important property. Although improving the other properties with complete replacement is not beneficial, a detailed investigation into this ineffective percentage revealed that, according to the results, the ideal replacement ratio is 60% walnut shells and 40% limestone, which results in optimal performance. Full article

(This article belongs to the Special Issue Sustainable Composite Construction Materials, Volume II)

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30 pages, 10187 KiB

Open AccessArticle

Characterization of Electrospun PAN Polymer Nanocomposite Membranes for CO₂/N₂ Separation

by Dirar Aletan and Jacob Muthu

J. Compos. Sci. 2025, 9(1), 21; https://doi.org/10.3390/jcs9010021 - 6 Jan 2025

Viewed by 493

Abstract

The focus of this study was to enhance the CO₂ capture capabilities of polyacrylonitrile (PAN) nanocomposite membranes by reinforcing them with multi-walled carbon nanotubes (MWCNT) and silica (SiO₂). These nanocomposite membranes were created using electrospinning technology, which produced nonwoven nanofiber [...] Read more.

The focus of this study was to enhance the CO₂ capture capabilities of polyacrylonitrile (PAN) nanocomposite membranes by reinforcing them with multi-walled carbon nanotubes (MWCNT) and silica (SiO₂). These nanocomposite membranes were created using electrospinning technology, which produced nonwoven nanofiber membranes. The nanoparticles were functionalized using Gum Arabic (GA) to improve the distribution and prevent agglomeration. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis were conducted to examine the functionalization of nanoparticles and their morphological structures. The membranes were experimentally characterized to obtain the CO₂ absorption properties and also to evaluate CO₂/N₂ permeation properties compared to pure PAN membranes. The results showed that higher nanoparticle concentrations increased CO₂ permeability while maintaining stable N₂ permeability, ensuring favorable CO₂/N₂ selectivity ratios. The 4 wt.% MWCNTs nanocomposite membrane achieved the best CO₂/N₂ separation with a CO₂ permeability of 289.4 Barrer and a selectivity of 6.3, while the 7 wt.% SiO₂ nanocomposite membrane reached a CO₂ permeability of 325 Barrer and a selectivity of 7. These findings indicate significant improvements in CO₂ permeability and selectivity for the nanocomposite membranes compared to pure PAN membranes. The Maxwell mathematical model has been used to validate the experimental results. The experimental results of the CO₂ separation properties of the nanocomposite membranes exceeded the predicted values by the mathematical models. This might be due to the well-dispersed nanoparticles and functional groups. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

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