Functional Composite Materials最新文献

Hemp fiber reinforced epoxy composites are increasingly being explored for lightweight structural and semi-structural applications, particularly in automotive and construction sectors, although their delamination resistance and temperature-dependent performance remain insufficiently understood. This study investigates the interlaminar fracture toughness of epoxy composites reinforced with untreated hemp fabrics (i.e., UTHE), treated hemp fabrics (i.e., THE), and treated hemp fabrics reinforced with 0.2 wt% CNT-incorporated epoxy composites (i.e., 0.2% CNT-THE) at room temperature (RT), 50 °C, and 70 °C. The G_IIC of 0.2% CNT-THE was higher than UTHE by ~ 80%, ~ 96%, ~ 86% at RT, 50 °C, 70 °C, respectively. This indicates the synergistic influence of alkali treatment of hemp fabrics and CNT addition to epoxy on the G_IIC. As temperature increased from RT to 50 °C, the G_IIC of UTHE, THE and 0.2% CNT-THE dropped by ~ 23%, ~ 38%, and ~ 16%, respectively. Surprisingly, as temperature increased from RT to 70 °C, the G_IIC of all the UTHE, THE and 0.2% CNT-THE dropped by ~ 64%. THE composites were more sensitive to high temperatures due to the lower T_g as determined from differential scanning calorimetry. The improvement in fracture toughness resulting from effect of alkali treatment which removes impurities from fiber surface and addition of CNTs which bridges the cracks and arrests the river lines besides enhancing the stress transfer from epoxy to hemp fiber as confirmed by scanning electron microscopy, supported by contact angle measurement.

The urgent transition towards sustainable energy technologies has intensified interest in nanocomposite materials that combine complementary physicochemical properties beyond those achievable with individual components. By integrating multiple nanoscale constituents, nanocomposites enable tailoring of electrical, mechanical, thermal, and interfacial properties, making them promising materials for next-generation energy technologies. This review critically examines recent advances in the rational design, synthesis, and characterisation of nanocomposites for energy conversion, including solar cells and fuel cells, and energy storage, including supercapacitors (SCs) and lithium-ion batteries (LIBs). This review emphasises structure–interface–property–performance relationships and the mechanisms by which nanocomposite architecture influences charge and ion transport, reaction kinetics, structural stability, and device performance. Beyond summarising recent developments, this review critically evaluates emerging material architectures, interfacial engineering strategies, and scalable fabrication approaches, together with the trade-offs between laboratory-scale performance and practical implementation. Finally, it assesses key challenges related to long-term durability, reproducibility, cost, environmental sustainability, and end-of-life considerations. Future research priorities are proposed to guide the development of nanocomposite materials towards durable, scalable, and sustainable energy conversion and storage technologies.

Bamboo as a natural fiber reinforced composite material possesses anisotropic mechanical properties. The highest strength and stiffness are found when bamboo was loaded along the longitudinal direction of fibers. Therefore, evaluating the elastic modulus of bamboo along its longitudinal direction is necessary for structural design. In this work, a nondestructive, dynamic testing method of free vibration was used to measure the elastic constant of bamboo in the longitudinal direction. Specimens with various lengths were tested under bending vibration conditions to determine the damped frequencies and damped periods through the Fast Fourier Transform (FFT). Then, the fundamental solution to the Euler-Bernoulli equation for free vibration was used to calculate the elastic moduli. It is found that the moduli of elasticity for specimens with various lengths were in the range from 14.1 to 16.7 GPa under two different loading configurations. The static tests by three-point bending produced elastic modulus results of as received bamboo: 14.24 ± 0.57 GPa for loading configuration 1 and 14.58 ± 0.08 GPa under loading configuration 2. The elastic moduli varied from as low as 11 to as high as 19 GPa depending on the moisture contents and testing methods. It is concluded that both static and dynamic tests delivered close elastic modulus values. The dynamic test results are slightly higher than the static ones due to the deformation rate effect. Moisture content in bamboo has significant effect on the stiffness of the composite. The higher the moisture content, the lower the stiffness of the bamboo. The overall deviation of the dynamic testing for determining the elastic modulus is about 5.74% considering the errors from geometry, density, and frequency measurements.

The structural integrity and electrical reliability of wearable electronics heavily depend on the physical properties of the underlying substrate. While previous research established a theoretical framework for modeling electrical degradation in specific printed nonwovens, this study expands that scope by providing a comprehensive comparative analysis of two distinct substrates: Evolon and Tyvek. Three silver-based conductive inks with different rheological characteristics (according to manufacturers’ data) were screen-printed onto both materials to evaluate their performance under the mechanical stress of repeated washing cycles. We applied a longitudinal damage model to quantify the progressive degradation of the transmission lines. The experimental findings reveal a significant contrast in failure mechanisms dictated by the substrate’s architecture. Although Tyvek exhibited lower initial Direct Current (DC) resistance, the printed circuits on this substrate suffered catastrophic electrical failure during the washing tests. Conversely, the porous, hydro-entangled structure of Evolon facilitated better ink integration, resulting in a measurable, progressive damage evolution that depended on the ink formulation. This comparative assessment underscores the critical role of substrate-ink compatibility in maintaining electrical stability and provides a predictive approach for designing durable, washable e-textiles.

Growing environmental concerns, ethical considerations, and the increasing demand for sustainable materials have accelerated the development of plant fibre-based vegan leather as a promising alternative to conventional animal leather. Most vegan leather materials are engineered as composite structures in which reinforcing plant fibre substrates provide the mechanical strength, flexibility, and durability required for practical applications. As the reinforcement material largely determines the overall performance and application potential of these composites, this review aims to critically evaluate global research trends, emerging themes, and knowledge gaps in plant fibre-based vegan leather through a bibliometric-guided analysis. Publications published between 2012 and 2025 were retrieved from Lens.org, Web of Science, and Google Scholar, and analysed using VOSviewer to examine publication trends, author collaborations, institutional contributions, and thematic evolution. The analysis revealed a substantial increase in research activity, particularly between 2019 and 2022, reflecting growing scientific interest in sustainable biomaterials. Hemp and jute remain the most extensively investigated reinforcement fibres, whereas pineapple leaf fibre (PALF) has emerged as a promising material with considerable innovation potential. Research has increasingly focused on sustainability, biotechnology, bio-based composites, material performance, circular economy principles, and environmentally responsible textile processing. However, the field continues to show limited integration of socio-economic, policy, and industrial perspectives, while collaborative research networks remain relatively centralized. This review identifies critical research gaps related to life cycle assessment, fabrication process standardization, performance benchmarking, and industrial scalability. By integrating bibliometric evidence with critical analysis, this review identifies current research trends, knowledge gaps, and future directions for the development of sustainable plant fibre-based leather technologies.

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Magnetically responsive carbon fibres that can be actively aligned during composite manufacturing are of interest for improving the load bearing applications of fibre-reinforced lightweight structures. This work investigates thermal and chemical pretreatment methods to remove the epoxy sizing layer and enable a uniform galvanic coating with Fe-Co. Since the epoxy-based sizing layer on commercial carbon fibres limits wettability and prevents uniform metal deposition, its removal is essential for successful coating. To address this, thermal pretreatment was carried out between 350 °C and 500 °C in air while chemical pretreatment involved acetone and nitric acid. Thermal treatment in air progressively improves fibre dispersibility with increasing temperature above 450 °C. Acetone treatment produces only minor improvements, whereas acid treatment enhanced dispersibility by oxidising the fibre surface and increasing its polarity. Limited coating coverage is obtained after low-temperature thermal treatment and acetone treatment, while fibres pretreated thermally at 450–500 °C show continuous and uniform coatings. Acid treatment further improves coating coverage compared with acetone but remains less effective than thermal desizing. The resulting Fe-Co coatings had an average thickness of approximately 1 μm with an average composition of 64% Fe and 36% Co. The magnetic properties of the Fe-Co coatings are described by its low coercivity (approximately 30 Oe) and high saturation magnetisation (approximately 80 emu/g). Overall, thermal desizing at 450 °C and above proved to be the most effective pretreatment for producing homogeneous magnetic Fe-Co coatings on carbon fibres.

This study investigates the influence of chemical fiber treatments alkaline (NaOH), benzoylation, and acetylation on the physical and tensile properties of RC fiber/ cassava starch biocomposites. RC fibers were extracted using mechanical lamination followed by water retting, then chemically modified to reduce hydroxyl group activity and enhance fiber–matrix adhesion. We also extracted starch from bitter cassava. Treated and untreated fibers were mixed with cassava starch (CS) through melt blending and compression molding. Physical testing were evaluated by mesuring Water absorption, density, solubility and biodegradability of different biocomposites while tensile performance was assessed via Universal Testing Machine (UTM). The results indicated that chemical treatments significantly reduced moisture uptake and improved interfacial bonding. Alkali-treated composites exhibited an 18% increase in tensile strength, while acetylated fiber composites showed a 32% reduction in water absorption compared to untreated composites. These findings demonstrate the effectiveness of chemical surface modification in enhancing the durability and performance of RC/cassava starch biocomposites, highlighting their potential for applications in automotive components, packaging, and sustainable construction materials.

Composites of high-density polyethylene (HDPE) and graphene nanoplatelets (GNP) were prepared by melt mixing and the effect of nanoplatelet geometry, (GNP-1, larger lateral size; nominal < 26.5 μm) and GNP-2 (smaller lateral size; nominal < 10 μm) and processing regime on mechanical properties studied. Increasing GNP-1 content had a pronounced stiffening effect at higher loadings (> 6 wt%), with tensile modulus increasing from ~ 1.40 GPa (neat HDPE) to ~ 3.55 GPa at 30 wt% (an increase of ~ 154%) and tensile strength rising by ~ 33% to ~ 35.5 MPa. Conversely, impact strength decreases continuously from ~ 28.5 to ~ 9.0 kJ m⁻² with increasing GNP loading (~ 68% decrease), while ductility shows a non-monotonic response. Elongation at break peaks at ~ 385% at 0.5 wt% and declines to ~ 40% at 30 wt% loading. The mechanical trends are consistent with interfacial slip-dominated deformation at low (< 6 wt%) GNP-1 loadings, whereas such mechanisms contribute less under rapid, crack-driven notched impact loading. At a fixed loading (1.25 wt%), platelet type strongly influences post-yield behaviour. HDPE/GNP-2 and HDPE/GNP-1 exhibit similar modulus (~ 1.4 GPa), yet elongation increases by 234% for HDPE/GNP-2 relative to HDPE/GNP-1, coinciding with an increase in crystallinity (from 72.5% to 76%). Additive selection further improves extensibility at constant GNP-1 content (1.25 wt%), the inclusion of a (PVCL–PVAc–PEG) copolymer when combined with a slip-agent (cis-13-docosenamide) results in an increase elongation (~ 150% to ~ 350%) without losses in tensile modulus and strength. Overall, the additive-enabled ductility enhancement is consistent with stabilization of necking and drawing under quasi-static tension via time-dependent interfacial shear and platelet sliding/pull-out in layered fracture regions.

Stretchable electronics require materials that maintain their electrical performance even under significant mechanical strain. The dielectric constant is important for figuring out device sensitivity, operating voltage, and energy density. However, there is extensive research on stretchable polymers, elastomers, energy harvesting devices, and composite dielectrics, and the dielectric constant, but data remain inconsistent and fragmented to predict materials and device design. This review examines the role of the dielectric constant in stretchable electronic materials, as well as measurement approaches and modelling strategies. It includes contributions to the key classes of materials, composite dielectrics, elastomers, and stretchable polymers and examines the relationships among materials, dielectrics, device sensitivity, operating voltage, and energy density as they are mechanically strained. Several studies have measured the dielectric constants of stretchable electronic materials. These studies demonstrate the variety of differences in dielectric constant that occur due to different conditions of the test or different compositions of the materials and indicate the need to have a more unified understanding of the structure-property relationships. However, limited open access data and the lack of standardised measurement methods make accurate analysis challenging and affect device performance. Solving these challenges through standardised measurement practices and the sharing of open datasets will play a crucial role in advancing the rational design of future stretchable, electronic, and energy-harvesting devices.

The development of sustainable refractory ceramics requires alternative silica sources capable of reducing the consumption of conventional raw materials without compromising thermo-mechanical performance. Although rice husk silica (RHS) has been investigated as a silica source, the combined effect of high RHS replacement levels and low steel fibre (SF) contents on the mechanical and thermal behaviour of refractory ceramics remains poorly understood. This study investigates refractory ceramic composites produced by replacing refractory clay with 10, 20 and 30% RHS and incorporating a low content of short steel fibres (1%). The influence of RHS and fibres on phase evolution, physical properties, flexural behaviour and thermal shock resistance was experimentally evaluated. The incorporation of RHS promoted matrix densification, increasing bulk density and reducing apparent porosity, which resulted in improved flexural strength up to 20% replacement. At 30% RHS, despite the lower porosity, flexural strength decreased, indicating that phase evolution, particularly the increased formation of cristobalite, also influences the mechanical response. The addition of steel fibres slightly increased porosity and reduced peak flexural strength, while introducing post-crack load-carrying capacity and changing the fracture behaviour from brittle to quasi-brittle. This change also significantly improved thermal shock resistance, increasing the number of thermal cycles to failure by approximately six times compared with unreinforced ceramics. X-ray diffraction confirmed the formation of mullite, quartz and cristobalite after sintering. The composite containing 20% RHS and 1% steel fibres exhibited the best overall balance between strength, ductility and thermal shock resistance, demonstrating that agricultural waste combined with a low fibre content provides an effective strategy for developing sustainable refractory ceramics with improved performance.

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