Fibers and Polymers最新文献

To accurately evaluate fabric appearance characteristics—such as smoothness, crease retention, and seam flatness—often affected by color and pattern interference, this study proposes an optimized algorithm based on binocular stereo vision. The goal is to capture the fine-grained surface topography of fabrics for precise analysis of wrinkle features. A binocular depth camera is used for data acquisition, and an enhanced RAFT-D algorithm is adopted for disparity estimation. By integrating pixel grayscale, gradient features, and local smoothness constraints, the algorithm establishes a robust similarity metric, enabling accurate matching of geometrically calibrated stereo image pairs and generating high-density, continuous disparity maps. According to depth reconstruction principles in computer vision, the disparity data are further converted into 3D point clouds representing the fabric surface. To validate the effectiveness of the proposed method, reconstruction results from a high-precision handheld 3D scanner are used as a reference. Both quantitative and qualitative evaluations show that the algorithm achieves an overall matching success rate of 90.8% across all fabric samples, demonstrating its superior accuracy and reliability in practical 3D fabric reconstruction applications.

Composite materials have gained significant attention due to their high strength-to-weight ratio and sustainability. In particular, natural fiber-reinforced composites are increasingly investigated as environmentally friendly alternatives to synthetic counterparts. This study focuses on fabricating lightweight and biodegradable luffa fiber-reinforced natural rubber (LNR) composites using compression molding, emphasizing optimizing key processing parameters—temperature, curing time, and compression pressure. Latex-form natural rubber was selected as the matrix owing to its biodegradability, low cost, and compatibility with natural fibers. In contrast, luffa fiber served as reinforcement due to its favorable mechanical properties. The Design of Experiments (DOE) approach, specifically Taguchi’s method, was employed to systematically analyze the influence of processing parameters on physical and mechanical performance. Experimental evaluation of mechanical properties was conducted according to ASTM standards. The rule of mixture was used to evaluate the mechanical properties analytically. The multiscale material modeling finite element (FEM) methods were used to assess the orthotropic properties using the representative volume element technique. Results showed that density was only marginally affected by processing conditions, with ROM and FEM generally overestimating values; however, FEM provided closer agreement to experimental data. Shore A hardness and longitudinal modulus highly depended on curing temperature and time, with optimal properties obtained at 100 °C for 15 min under 1.0 MPa pressure. Similarly, the maximum ultimate tensile strength (0.40 MPa) was achieved under the same conditions, attributed to enhanced fiber–matrix bonding and crosslinking. Statistical analysis (ANOVA) confirmed temperature as the most influential parameter, followed by pressure and curing time. Optimized processing conditions significantly improved fiber–matrix adhesion, resulting in superior mechanical performance. These findings provide reliable processing guidelines for developing high-performance, environmentally sustainable LNR composites, making them suitable for high-impact applications in defense and consumer sectors.

A novel spinning method that integrates electrospun nanofiber strips into yarn structures has been developed to produce multifunctional yarns. The resulting yarn exhibited a core-sheath structure, with a core composed of tannic acid-modified magnesium hydroxide/thermoplastic polyurethane (TA@MH/TPU) nanofiber strip, sheathed by either pure cotton or cotton/sodium alginate blended fibers. The TA modification improved the dispersion of MH within the TPU matrix, leading to enhanced membrane strength compared to unmodified MH/TPU at equal loadings. The film containing 7% TA@MH/TPU demonstrated optimal mechanical properties (breaking strength of 1.43 MPa, elongation of 122.93%), flame retardancy (limiting oxygen index of 27.1%), and antibacterial efficacy killing ratios of 80.87% against E. coli and 85.07% against S. aureus. Yarns fabricated with this film, the TA@MH/TPU-cotton (CMSCY) retained the antibacterial functionality (67.48% against E. coli and 79.05% against S. aureus), and the TA@MH/TPU-cotton/sodium alginate (C/SAMSCY) achieved the flame retardancy with a limiting oxygen index of 27.8%. Notably, the CMSCY yarn showed a high tensile strength of 1.53 MPa, which was 15 times that of the TA@MH/TPU nanofiber film, addressing the application limitations of nanofiber membranes caused by their low mechanical strength. Given that electrospun membranes can be readily functionalized, this spinning method offers a promising strategy for producing composite yarns, particularly for developing multifunctional textile fabrics.

In order to meet the growing demand for flexible wearable electronic products, flexible piezoelectric nanogenerators have received widespread attention as a sustainable power source in wireless mobile devices. This article reported Barium Titanate/Polyacrylonitrile (BaTiO₃/PAN) composite nanofiber membranes prepared via electrospinning technology to successfully disperse high dielectric constant BaTiO₃ with varied concentration in PAN solution. The increase of BaTiO₃ particles helps to improve the output voltage of PAN nanofibers, and the output performance of BaTiO₃/PAN flexible composite piezoelectric nanogenerator is the best with an output voltage of 1.6 V and current of 5.6 nA, respectively, when the mass fraction of BaTiO₃ is 15%. Such BaTiO₃/PAN composite nanofiber membrane also exhibits excellent flexibility, plus an outstanding stability of the synthesized BaTiO₃/PAN composite nanofiber membrane piezoelectric nanogenerator after 2000 cycles of mechanical testing, which enables it to have an enormous potential in wireless sensing and wearable device applications. Therefore, this BaTiO₃/PAN piezoelectric nanogenerator can detect the current signals of the human body in states, such as elbow bending, knee bending, running, and breathing, providing a reference for the development of high-performance and self-powered wearable bioelectronic products.

Amid growing environmental concerns and tightening regulations on hazardous fluorochemicals, fluorine-free waterproofing agents have emerged as sustainable alternatives to conventional fluorinated systems (e.g., C6, C8). This study comprehensively evaluates the performance of modern non-fluorinated agents—polyurethane-based (Zelan R3, TF-5015) and acrylic-based (NR-7565, DM-3696) formulations—against traditional fluorinated counterparts on nylon textiles. Results demonstrate that fluorine-free agents achieve a water repellency rating of 5 grades at 15 g/L application concentration, whereas fluorinated systems require only 6 g/L to attain equivalent hydrophobicity. However, polyurethane-based fluorine-free agents exhibit exceptional durability, outperforming both acrylic-based and fluorinated systems under extreme conditions: water contact angle (WCA) reductions remain minimal (5°–10°) after exposure to strong acid (pH 1), alkali (pH 13), and boiling water immersion. These systems also display superior wash fastness, with a marginal 0.5-grade decline in water repellency after 30 laundering cycles, and moderate abrasion resistance (WCA reduction ≤ 14 after 1600 Martindale cycles). Furthermore, fluorine-free treatments confer enhanced anti-fouling and self-cleaning functionality, effectively repelling dyes and common liquid contaminants while retaining performance post-treatment. The advancements are attributed to optimized molecular architectures, such as branched polyurethane chains, which enhance crosslinking density and hydrophobic stability without fluorinated components. This work confirms that contemporary fluorine-free agents can rival or surpass fluorinated counterparts in durability, multifunctionality, and environmental safety, albeit with slightly higher application demands for hydrophobicity. The findings underscore the feasibility of transitioning to eco-friendly waterproofing technologies without compromising industrial performance, offering critical insights for developing sustainable textiles aligned with circular economy principles and global regulatory trends. Future efforts should focus on refining application efficiency to bridge the performance-concentration gap while maintaining cost-effectiveness.

Poly-fiber composites hold significant potential for applications requiring a high strength-to-weight ratio. These composites are developed using natural fibers, which are cost-effective and offer improved functional behavior. However, the contribution of single fibers and moisture absorption can negatively affect the overall performance of the composite. Current research aims to synthesize and enhance the mechanical and thermal properties of hybrid nanocomposite laminates containing glass (G), kenaf (K), and jute (J) fibers. The fiber sequence arrangements studied are G/K/K/K/K/J/J/J/G, G/K/K/J/J/J/J/K/K/G, and G/J/J/K/K/K/K/J/J/G, each featuring 0, 1, 2, and 3 wt.% of nano-multi-walled carbon nanotubes (MWCNT) produced using the hand layup combined with compression molding method. The mechanism for nano-MWCNT on the mechanical, water absorption, and thermal behavior of hybrid composite laminates is evaluated. Among the various sequences, the hybrid laminates with the sequences of G/J/J/K/K/K/K/J/J/G adopted with 3 wt.% MWCNT are found optimum tensile strength (101 MPa), flexural strength (136 MPa), microhardness (84 HV), fracture toughness (2.57 MPa^0.5), and reduced water absorption behavior of 3.45% for 48 h. Moreover, the 3 wt.% MWCNT featured composite series of G/J/J/K/K/K/K/J/J/G exhibits superior thermal stability between 200 and 250 °C, with a reduced mass loss of 20% observed. Thermo-gravimetric analysis (TGA) measurements demonstrated better thermal stability as MWCNT concentration increased. This work demonstrates the potential of MWCNT-reinforced natural fiber composites for automotive interior door panel applications.

Low-frequency vibrations can significantly affect human comfort and health, particularly in heavy commercial vehicles where long-term exposure is common. To address this issue, this study proposes a hybrid composite material by combining Ecoflex with Warp-Knitted Spacer Fabric (WKSF), resulting in an Ecoflex-Reinforced Fabric (ERF) composite with enhanced damping performance. Five types of ERF composites were fabricated with varying Ecoflex contents and tested under sinusoidal vibrations in the 0–100 Hz range. Among them, the sample with an intermediate Ecoflex content (SAM3) exhibited the highest damping ratio of 91.91% at 100 Hz. A vibration damping system was then developed by integrating the SAM3-ERF composite with a Macro-Fiber Composite (MFC) actuator. The system was evaluated across various frequencies to assess its vibration attenuation capability. Notably, the highest damping ratio of 93.21% was achieved at 70 Hz, and the system maintained an effective damping bandwidth of approximately 55 Hz, defined as the range where the damping ratio exceeded 50%. These findings demonstrate the feasibility of designing flexible, lightweight, and stable damping systems for a wide range of low-frequency vibration applications, particularly in automotive, aerospace, and wearable technologies requiring both adaptability and vibration damping.

A series of fluorinated copolyimides containing non-coplanar triphenylamine (TPA) units was synthesized from 4,4′-diamino-3′′,5′′-difluorotriphenylamine (DMTPA), 4,4′-oxydianiline (ODA), and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) through high-temperature polycondensation. The resulting copolyimides exhibited high thermal stability, good solubility in common organic solvents, optical transparency, and enhanced hydrophobicity. Wide-angle X-ray diffraction (WAXD) and molecular simulations confirmed that the bulky fluorinated TPA units increased interchain spacing and fractional free volume (FFV), thereby facilitating gas transport. Gas permeation measurements at 35 °C and 4 bar revealed that CO₂ permeability increased with TPA content, whereas CO₂/N₂ selectivity remained nearly constant (~ 21). The best-performing membrane (DFPI-5) achieved a CO₂ permeability of 24.93 Barrer with a CO₂/N₂ selectivity of 21.31, approaching the 2008 Robeson upper bound. These findings underscore the effectiveness of fluorinated, non-coplanar TPA moieties in tailoring polyimide membranes for advanced gas separation.

The flexible yarn actuator driven by wetting is advantageous in environmental adaptability as smart wearable elements. Here, two-dimensional alginate fiber yarns were prepared by blending alginate fiber with viscose fiber to enhance the spinnability and hygroscopicity of alginate fiber. Polyvinyl alcohol (PVA) and glutaraldehyde (GA) were cross-linked with alginate fiber blended yarns. The alginate yarn actuator was prepared by imitating spiral plant vines and stems and optimized by varying processing parameters as well as simulated with Finite Element Software. The results show that the shrinkage of different blended ratios is consistent at relative humidity from 20 to 40%, but after 40%, the shrinkage of blended yarn actuator with alginate/viscose fibers of 40/60 is significantly greater than that of 50/50, showing an excellent actuation among the three physical blended yarns. The contraction of yarn actuator model demonstrates consistent tendency with the experimental results. After modified with PVA and GA, hydrophilicity of the blended yarns is further increased. The shrinkage ratio of the yarn actuator is 29.09% at 5% PVA concentration. During the biomimetic preparation, the shrinkage ratio of yarn actuator increases with the twist number while decreases with the coil number. Meanwhile, the work capacity of yarn actuator increases with load weight and decreases with coil yarn number. At linear density of 240 tex, twist of 500 twists /m, load weight of 1.8 g and coil number of 4 coils /cm, the maximum shrinkage ratio of PVA modified yarn actuator reaches 50.18%. The chemically modified alginate yarn actuator shows high stability.

The elevated temperatures affect the service performance of the fibre-reinforced polymers. To improve performance at elevated temperatures, four types of interlayer hybrid woven fibre-reinforced polymer thin-walled tubes (HFRPTTs) were designed and prepared (all-carbon fibre H_C4FRPTT, glass-carbon fibre H_G1C3FRPTT, Kevlar–carbon fibre H_K1C3FRPTT, and basalt-carbon fibre H_B1C3FRPTT). The change rate of mass loss was obtained at different elevated temperatures (100 ℃, 200 ℃, 300 ℃, 400 ℃). Quasi-static axial compression tests and industrial microscopy were employed to analyse the variations in mechanical properties, energy absorption characteristics, and microstructural changes. Digital scanning calorimetry (DSC) and thermal gravimetry analysis (TGA) studied the thermomechanical characteristics before and after exposure to elevated temperatures. The results show that the mass loss rate of Kevlar fibre is the highest, leading to the maximum mass loss rate for H_K1C3FRPTT. The mechanical properties of HFRPTTs (compressive strength, specific strength, and peak load) are influenced by the competing effects of resin matrix post-curing and thermal degradation. The critical temperature for HFRPTTs lies between 300 and 400 ℃. Below 300 ℃, the failure mode of HFRPTTs is a stable annular folding. The energy absorption characteristics of HFRPTTs are influenced by the combined effects of resin post-curing, thermal degradation, and mass loss. The variation patterns of HFRPTT's performance at different temperatures provide a reference for its service.