Journal of Composites Science

Currently, electrochemical devices and portable electronic equipment play a significant role in people’s daily lives. Zinc-ion batteries (ZIBs) are growing rapidly due to their excellent safety, eco-friendliness, abundance of resources, and cost-effectiveness. The application of biomass as a polymer separator is gradually expanding in order to promote a circular economy and sustainable materials. This research focuses on the usage of cellulose fibers obtained from coffee parchment (CP) waste. The extracted cellulose fibers are produced via both mechanical and chemical methods. The sustainable separators are fabricated through vacuum filtration using a polymer filter membrane. The impact of incorporating silica particles and varying silica content on the physical and electrochemical properties of a cellulose-based separator is examined. The optimum amount of silica integrated into the cellulose separator is determined to be 5 wt%. This content led to an effective distribution of the silica particles, enhanced wettability, and improved fire resistance. The ZIBs incorporating cellulose/recycled silica at 5 wt% demonstrate exceptional cycle stability and the highest capacity retention (190% after 400 cycles). This study emphasizes the promise of sustainable polymers as a clean energy resource, owing to their adaptability and simplicity of processing, serving as a substitute for synthetic polymers sourced from fossil fuels. Full article

CFRP (carbon fiber-reinforced polymer) production in Europe is approximately 10,000 metric tons annually, and according to the UK authorities, approximately 35% of end-of-life CFRP waste is currently landfilled. The authors propose a novel recycling process for industrial CFRP waste particles to produce the core of a sandwich CFRP panel through the direct molding method. Industrial CFRP powder from grinding operations was collected, sieved and molded into square panels with and without external skins of virgin CFRP prepreg. Thermogravimetric (TGA) and differential scanning calorimetry (DSC) analysis revealed thermal activation (~70 °C), indicating potential for reprocessing. This study proposes a novel recycling route that directly molds industrial CFRP grinding waste into the core of sandwich structures, with or without virgin CFRP prepreg skins. Key findings: thermal re-processability was confirmed through TGA and DSC, showing activation near 70 °C; electrical conductivity reached 0.045 S/cm through the thickness in sandwich panels, with recycled cores maintaining comparable conductivity (0.04 S/cm); mechanical performance was improved significantly with prepreg skins, as evidenced by three-point bending tests showing enhanced stiffness and strength. These results demonstrate the potential of recycled CFRP waste in multifunctional structural applications, supporting circular economy goals in composite materials engineering. Full article

The thermal, thermomechanical, and viscoelastic properties of continuous unidirectional (UD) glass fiber/high-density polyethylene (GF/HDPE) and ultra-high-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) tapes are characterized in this paper in order to support their use in extreme environments. Unlike prior studies that focus on short-fiber composites or limited thermal conditions, this work examines continuous fiber architectures under five operational environments derived from Army Regulation 70-38, reflecting realistic defense-relevant extremes. Differential scanning calorimetry (DSC) was used to identify melting transitions for GF/HDPE and UHMWPE/HDPE, which guided the selection of test conditions for thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA). TMA revealed anisotropic thermal expansion consistent with fiber orientation, while DMA, via strain sweep, temperature ramp, frequency sweep, and stress relaxation, quantified their temperature- and time-dependent viscoelastic behavior. The frequency-dependent storage modulus highlighted multiple resonant modes, and stress relaxation data were fitted with high accuracy (R² > 0.99) to viscoelastic models, yielding model parameters that can be used for predictive simulations of time-dependent material behavior. A comparative analysis between the two material systems showed that UHMWPE/HDPE offers enhanced unidirectional stiffness and better low-temperature performance. At the same time, GF/HDPE exhibits lower thermal expansion, better transverse stiffness, and greater stability at elevated temperatures. These differences highlight the impact of fiber type on thermal and mechanical responses, informing material selection for applications that require directional load-bearing or dimensional control under thermal cycling. By integrating thermal and viscoelastic characterization across realistic operational profiles, this study provides a foundational dataset for the application of continuous fiber thermoplastic tapes in structural components exposed to harsh thermal and mechanical conditions. Full article

Three-dimensional concrete printing (3DCP) is an emerging technology that improves design flexibility and material efficiency in construction. However, widespread adoption of 3DCP requires overcoming key material challenges. These include controlling rheology for pumpability and buildability and achieving sufficient mechanical strength. This paper provides a comprehensive review of the application of nanoclays (NCs) as a key admixture to address these challenges. The effects of three primary NCs (attapulgite (ATT), bentonite (BEN), and sepiolite (SEP)) on the fresh- and hardened-state properties of printable mortars are systematically analyzed. This review summarize findings on how NCs enhanced thixotropy, yield stress, and cohesion, which are critical for shape retention and the successful printing of multilayered structures. Quantitative analysis reveals that optimized dosages of NCs can increase compressive strength by up to 34% and flexural strength by up to 20%. For enhancing rheology and printability, a dosage of approximately 0.5% by binder weight is often suggested for ATT and SEP. In contrast, BEN can be used at higher replacement levels (up to 20%) to also function as a supplementary cementitious material (SCM), though this significantly impacts workability. This review consolidates the current knowledge to provide a clear framework for selecting appropriate NCs and dosages to develop high-performance, reliable, and sustainable materials for 3DCP applications. Full article

This review is focused on glass fibers and natural fibers, exploring their applications in vehicles and buildings and emphasizing their significance in promoting sustainability and enhancing performance across various industries. Glass fibers, or fiberglass, are lightweight, have high-strength (3000–4500 MPa) and a Young’s modulus range of 70–85 GPa, and are widely used in automotive, aerospace, construction, and marine applications due to their excellent mechanical properties, thermal conductivity of ~0.045 W/m·K, and resistance to fire and corrosion. On the other hand, natural fibers, derived from plants and animals, are increasingly recognized for their environmental benefits and potential in sustainable construction, offering advantages such as biodegradability, lower carbon footprints, and reduced energy consumption, with a sound absorption coefficient (SAC) range of 0.7–0.8 at frequencies above 2000 Hz and thermal conductivity range of 0.07–0.09 W/m·K. Notably, the integration of these materials in construction and automotive sectors reflects a growing trend towards sustainable practices, driven by the need to mitigate carbon emissions associated with traditional building materials and enhance fuel efficiency, as seen in hybrid composites achieving 44.9 dB acoustic insulation at 10,000 Hz and a thermal conductivity range of 0.05–0.06 W/m·K in applications such as the BMW i3 door panels. Natural fibers contribute to reducing reliance on fossil fuels, supporting a circular economy through the recycling of agricultural waste, while glass fibers are instrumental in creating lightweight composites for improved vehicle performance and structural integrity. However, both materials face distinct challenges. Glass fibers, while offering superior strength, are vulnerable to chemical degradation and can pose recycling difficulties due to the complex processes involved. On the other hand, natural fibers may experience moisture absorption, affecting their durability and mechanical properties, necessitating innovations to enhance their application in demanding environments. The ongoing research into optimizing the performance of both materials highlights their relevance in future sustainable engineering practices. In summary, this review underscores the growing importance of glass and natural fibers in addressing modern environmental challenges while also improving product performance. As industries increasingly prioritize sustainability, these materials are poised to play crucial roles in shaping the future of construction and transportation, driving innovations that align with ecological goals and consumer expectations. Full article

This study explores the fabrication of hydrophobic surfaces on polymer components via Digital Light Processing (DLP), with emphases on how texture geometry, feature dimensions, and resin type influence surface wettability. Square and cylindrical microtextures were fabricated and evaluated using static contact angle measurements. Square-shaped structures demonstrated enhanced hydrophobicity, with contact angles reaching 133.6°, compared to approximately 100° for cylindrical counterparts of identical dimensions. Increasing pillar height to 521 µm enhanced hydrophobicity by approximately 15%, while decreasing pillar spacing to 150 µm increased contact angles from 86.8° to 106°, highlighting the role of microstructure density. For square-shaped structures, the addition of a hydrophobic agent at 3 wt.% resulted in a contact angle of 123.4°, representing a 44% improvement over the untreated sample. These findings underscore the combined influence of resin chemistry, surface texture design, and dimensional parameters on wettability behavior. Although superhydrophobicity (contact angle > 150°) was not achieved, the study demonstrates notable advancements in optimizing hydrophobicity through DLP printing. Overall, the results support DLP as a scalable and cost-effective approach for engineering functional surfaces suited to self-cleaning, biomedical, and anti-fouling applications. Full article

This study presents a comparative investigation of 3Ni2Ce/Al catalysts synthesized via different methods dry impregnation (DI), capillary impregnation (CI), and solution combustion synthesis (SC) for the complete oxidation of methane. The aim was to elucidate the influence of the preparation method on the catalytic activity and reduction behavior of the catalysts. Among the samples tested, the catalyst prepared by the solution combustion method exhibited the highest activity: at 500 °C, the methane conversion reached 82%, compared to 43% and 41% for the 3Ni2Ce/Al (CI) and 3Ni2Ce/Al (DI) prepared catalysts, respectively. At 550 °C, the 3Ni2Ce/Al (SC) catalyst achieved 99% conversion, surpassing the 3Ni2Ce/Al (CI) (72.5%) and 3Ni2Ce/Al (DI) (95%) analogs. Hydrogen temperature-programmed reduction (H₂-TPR) analysis revealed that the 3Ni2Ce/Al (SC) catalyst exhibited enhanced hydrogen uptake in the range of 450–850 °C, indicating the presence of more easily reducible NiO species interacting with CeO₂ and the alumina support. Scanning electron microscopy (SEM) further confirmed a more uniform distribution of the active phase on the surface of the 3Ni2Ce/Al (SC) catalyst in comparison to the impregnated samples. Overall, the findings demonstrate that the preparation method has a significant impact on the development of a redox-active catalyst structure. The superior performance of the SC-derived catalyst in methane oxidation is attributed to its improved reducibility and homogenous morphology, making it a promising candidate for high-temperature catalytic applications. Full article

Recently, plastic and agricultural waste have gained attention as sustainable alternatives. Despite efforts to recycle these materials, much still ends up in landfills, raising environmental concerns. To optimize their potential, these wastes ought to be transformed into value-added products for diverse industrial applications. This work focused on producing thin composite material films using olive oil solid waste called JEFT and recycled plastic bottles. JEFT was cleaned, dried, and processed mechanically via ball milling to produce nano- and micron-sized particles. Composite films were produced via melt compounding and compression molding with a rapid cooling process for controlled crystallinity and enhanced flexibility. Their density, water absorption, tensile strength, thermal stability, water permeability, functional groups, and biodegradation were comprehensively analyzed. Results indicated that 50% JEFT in recycled plastic accelerated thermal deterioration (42.7%) and biodegradation (13.4% over 60 days), highlighting JEFT’s role in decomposition. Peak tensile strength (≈32 MPa) occurred at 5% JEFT, decreasing at higher concentrations due to agglomeration. Water absorption and permeability slightly increased with JEFT content, with only a 1% rise in water permeability for 50% JEFT composites after 60 days. JEFT maintained the recycled plastic’s surface chemistry, ensuring stability. The findings of this study suggest that JEFT/r-HDPE films show potential as greenhouse coverings, enhancing crop production and water efficiency while improving plastic biodegradation, offering a sustainable waste management solution. Full article

The variety of fiber types embedded in fiber-reinforced polymer (FRP) composites determines different tribology performance properties. In this work, the tribological properties under dry sliding conditions of glass fiber-reinforced polymer (GFRP) and basalt fiber-reinforced polymer (BFRP) were investigated and compared. Laminated composite specimens with different fiber content were manufactured by vacuum bagging and autoclave curing. Tensile and flexural mechanical properties, as well as pin-on-disk tribological properties of the composite specimens, were analyzed. A design of experiments was performed considering the influence of fiber weight fraction, fiber type, and sliding speed on the coefficient of friction (COF), specific wear rate (K), and contact temperature. A multifactorial ANOVA was performed to identify the significance and contribution percentage of each factor. Deep investigations to understand the wear mechanisms were performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results of the statistical analysis showed that the interaction between fiber type and sliding speed had the most significant influence on the COF (31.36%), while the fiber weight fraction had the predominant effect on the specific wear rate (22.04%), and the sliding speed was the most influential factor affecting temperature (82.88%). BFRP composites consistently performed better than GFRP in all tribological metrics, such as coefficient of friction, specific wear rate, and contact temperature. Full article

This study investigates the effect of rice husk content (0–60 wt.%) on the thermal, mechanical and rheological properties of polypropylene composites prepared by extrusion and injection molding. A temperature-invariant approach was applied to analyze the viscoelastic properties, allowing the combination of data obtained at different temperatures. The results show that as the husk content increases, the elastic modulus and hardness rise linearly, while the impact strength and elongation at break significantly decrease. Composites with 40–50% filler exhibit a balanced combination of strength and stiffness, as confirmed by the summary data in the table (provide references). The application of the temperature-invariant viscosity method confirmed its effectiveness in evaluating the flow properties of composite melts. The obtained results have practical significance for the development of eco-friendly polymer materials with natural fiber fillers. Full article

Random parametric errors (RPEs) are introduced into the model establishment of a laminated composite cantilever beam (LCCB) to demonstrate the accuracy and robustness of a recurrent neural network (RNN) in predicting the chaotic vibration of a LCCB, and a comparative analysis of training performance and generalization capability is conducted with a convolutional neural network (CNN). In the process of dynamic modeling, the nonlinear dynamic system of a LCCB is established by considering RPEs. The displacement and velocity time series obtained from numerical simulation are used to train and test the RNN model. The RNN model converts the original data into a multi-step supervised learning format and normalizes it using the MinMaxScaler method. The prediction performance is comprehensively evaluated through three performance indicators: coefficient of determination (R²), mean absolute error (MAE), and root mean square error (RMSE). The results show that, under the condition of introducing RPEs, the RNN model still exhibits high prediction accuracy, with the maximum R² reaching 0.999984548634328, the maximum MAE being 0.075, and the maximum RMSE being 0.121. Furthermore, performing predictions at the free end of the LCCB verifies the applicability and robustness of the RNN model with respect to spatial position variations. These results fully demonstrate the accuracy and robustness of the RNN model in predicting the chaotic vibration of a LCCB. Full article

Recently, environmental issues have compelled people worldwide to pursue sustainability and adopt circular economy practices across all engineering sectors, including polymer engineering and composite fabrication. A transition towards fabric-reinforced thermoplastics (FRTPs), a greener solution, has been recommended in recent years. On the other hand, utilizing recovered reinforcing phases, such as recycled carbon fiber (rCF), has attracted tremendous attention. In this framework, the aim of this research is to investigate the performance of acrylic-based FRTPs (Elium^® resin developed by Arkema). Woven virgin carbon fiber (vCF) and non-woven recycled carbon fiber (rCF) fabrics were used as reinforcement architectures for the fabrication of composites via resin infusion. The optimized formulation selected for the matrix showed flexural modulus and flexural strength of 5 GPa and 78 MPa, respectively. Composites prepared with woven vCF reached 36 GPa and 620 MPa values of flexural modulus and strength, respectively. The study of non-woven fabric is of particular interest, because the web is composed of recycled carbon fibers obtained from end-of-life (EoL) thermoset composite components. The results were promising; the flexural modulus reached 8 GPa, and the flexural strength was 113 MPa. Improvements are anticipated, especially in the parameters and conditions of the molding process. Full article

In recent years, agricultural biomass-filled materials have been increasingly explored as sustainable alternatives to fossil-based polymers and for the development of biocomposites. In this study, micronized hemp stalks, a byproduct of the cannabis industry, were loaded into 10–20% of polypropylene/polyethylene bicomponent fibers in a cost-effective original airlaying process. The production process was developed to achieve high hemp content (up to 80%), while maintaining suitable structural and mechanical properties. Experimental analyses confirmed that the hemp-based biocomposite exhibited promising thermal conductivity values (0.068 ± 0.002 W/mK) and effective sound-attenuation capabilities that are comparable to commonly used insulating materials, such as stone wool. Furthermore, X-ray diffraction and field emission scanning electron microscopy measurements analyzed the insulation features of the hemp-based biocomposite prepared with its morphological and structural properties, revealing its high internal porosity and polymeric crystallinity. These results highlight the potential of hemp biocomposites as sustainable, economically viable alternatives for thermal and acoustic insulation applications. Full article

The integrity analysis of a combustion chamber that uses Ablative Thermal Protection Systems (ATPSs) is a process that requires the analysis of the thermal and mechanical behavior of the materials involved and their interaction. A 1D thermal model for multilayered combustion chambers of hybrid rocket engines and solid rocket motors is developed, taking into consideration the thermal behavior of charring ATPSs during phase change and the capability of implementing an ablation process. A stress model is also implemented to assess the structural integrity of the combustion chamber that undergoes pressure and thermal loads. A numerical finite-difference model is used to implement analytical models and simulate the behavior of the materials. Bibliographic data and finite element analysis tools are used to evaluate and verify the models developed. Lastly, six different materials are used as a case study, and a parametric optimization is applied to obtain the minimum-mass designs using the materials selected. Full article

Conductive composites are a flexible class of engineered materials that combine conductive fillers with an insulating matrix—usually made of ceramic, polymeric, or a hybrid material—to customize a system’s electrical performance. By providing tunable electrical properties in addition to benefits like low density, mechanical flexibility, and processability, these materials are intended to fill the gap between conventional insulators and conductors. The increasing need for advanced technologies, such as energy storage devices, sensors, flexible electronics, and biomedical interfaces, has significantly accelerated their development. The electrical characteristics of composite materials, including metallic, ceramic, polymeric, and nanostructured systems, are thoroughly examined in this review. The impact of various reinforcement phases—such as ceramic fillers, carbon-based nanomaterials, and metallic nanoparticles—on the electrical conductivity and dielectric behavior of composites is highlighted. In addition to conduction models like correlated barrier hopping and Debye relaxation, the study investigates mechanisms like percolation thresholds, interfacial polarization, and electron/hole mobility. Because of the creation of conductive pathways and improved charge transport, developments in nanocomposite engineering, especially with regard to graphene derivatives and silver nanoparticles, have shown notable improvements in electrical performance. This work covers the theoretical underpinnings and physical principles of conductivity and permittivity in composites, as well as experimental approaches, characterization methods (such as SEM, AFM, and impedance spectroscopy), and real-world applications in fields like biomedical devices, sensors, energy storage, and electronics. This review provides important insights for researchers who want to create and modify multifunctional composite materials with improved electrical properties by bridging basic theory with technological applications. Full article

This article investigates the problem of bending failure in a rectilinear thin-walled rod consisting of a multimodular material exhibiting different elastic properties in tension and compression, with applications to the structural design of space satellites, unmanned aerial vehicles, aeronautical systems, and nano- and micro-class satellites. Nonlinear differential equations have been formulated to describe the propagation of the failure front under transverse loading. Formulas for determining the incubation period of the failure process have been derived, and the problem has been solved. Based on the developed model, new analytical expressions have been obtained for the displacement of the neutral axis, the stiffness of the rod, the distribution of maximum stresses, and the motion of the failure front. The influence of key parameters—such as the singularity coefficient of the damage nucleus and the ratio of the elastic moduli—on the service life and failure dynamics of the rod has been analyzed. Using the obtained results, the effect of the multimodular properties on the long-term strength of thin-walled rods under pure bending has been thoroughly studied. The analysis of the constructed curves shows that an increase in the “fading of memory” (memory-loss) parameter, which characterizes the material’s ability to quickly “forget” previous loadings and return to equilibrium, can, in certain cases, lead to a longer service life. Full article

This study presents the results of research on the use of Portland cement as a binder for producing semi-permanent molds intended for large-scale castings made from complex alloyed steels. Based on the conducted experiments, the optimal composition of a molding mixture based on Portland cement was determined to manufacture large molds with high operational performance. The technological properties of the mixtures were investigated, focusing on the flowability, sedimentation stability, and strength after curing. The recommended mixture composition is as follows: Portland cement—18.75%; sand—56.5%; quartz powder—25%; water—25%. To accelerate the hardening process, the use of curing accelerators is advised. The most effective additives are a 9% aluminum nitrate solution at 0.6–1.5% by weight or sodium aluminate at 3–4%. This composition ensures the required strength within a short curing time. A specific thermal treatment regime is also recommended to further stabilize the mold structure: heating to 450 °C at a rate of 75 °C per hour, holding for 2 h, followed by controlled cooling together with the furnace. Full article

Structural composite materials are being used more than ever in aeronautics, automotive and naval, or in renewable energies fields. To reconcile the contradictory needs for higher performances and lower costs, it is crucial to ensure the real-time monitoring of as many features as possible during the manufacturing process to feed a digital twin able to minimise post-fabrication controls. For thermoset composites, little information is available regarding the evolution of the polymer’s core properties during infusion and curing. The local kinetics of reticulation, in several areas of interest across the thickness of a structural composite part, are valuable data to record and analyse to guarantee the materials’ performances. This paper investigates a novel strategy curing in the core of an epoxy matrix with crosslinkable quantum-resistive nanocomposite sensors (xQRS). First, the electrical behaviour of the sensor during isothermal curing is considered. Then, the influence of the dynamic percolation and the epoxy crosslinking reaction on the resistance is examined. The evidence of a relationship between the curing state of the resin and the evolution of the xQRS resistance makes its use in the process monitoring of thermoset composites promising, especially in cases involving large and thick parts. Full article

Nanocomposites were synthesized from epoxidized natural rubber (ENR-50) and magnetite (Fe₃O₄) at 1, 5, and 9 wt.%, respectively. Various analyses were conducted to gain comprehensive insight into the properties of the nanocomposites. It was found that the ring epoxide units can be opened and bonded with the Fe moieties of the magnetite to form an Fe-O-C structure, as shown in FTIR spectra at 690 and 700 cm⁻¹. Peaks in UV-vis spectra at the wavelength of 297 nm shifted to 299, 303, and 309 nm for the nanocomposite samples with 1, 5, and 9 wt.% Fe₃O₄, respectively. XRD showed a decrease in the amorphous peak intensity, while new diffraction peaks emerged at 33° and 43°, indicative of the crystalline structure of the Fe₃O₄ in the nanocomposites. Based on TEM micrographs, it was found that the average size of Fe₃O₄ particles in the rubber matrix with 1 wt.% Fe₃O₄ was around 20 and 33 nm. SEM micrographs proved that nanoparticles with 1 wt.% Fe₃O₄ were regularly dispersed in the rubber matrix, and that magnetite nanoparticles were spherical in shape, as well as having strong interactions and bonding with the rubber matrix. A TGA thermogram showed three thermal steps of degradation across a wide temperature range, from 81 °C to 592 °C, and resistance to thermal degradation of the nanocomposite samples as compared to the rubber sample could be clearly observed. Furthermore, DCS showed higher Tg for nanocomposites at 24.4, 25.1, and 26.3 °C, respectively, compared to purified ENR-50 at −18.6 °C. Full article