Fibers and Polymers最新文献

Conventional controlled-release fertilizers (CRFs) contribute to microplastic pollution due to their non-degradable polymer coatings. The development of eco-friendly and biodegradable alternatives is essential for sustainable agriculture. This study aimed to fabricate and evaluate a biodegradable CRF system using calcium alginate (CaAlg) beads containing functional additives. CaAlg beads encapsulating urea were fabricated by the extrusion-dropping method. Polyvinyl alcohol (PVA) and citric acid (CA) were added to improve structural integrity, and humic acid (HA) was included as a functional filler. The physical properties, urea loading efficiency, and release profile of the beads were evaluated in this study. The actual performance of the CRF was evaluated through a 90-day carrot cultivation experiment by monitoring plant growth and soil nitrogen levels. The results showed a trade-off in that higher crosslinking density decreased the urea loading (from 84.9% to 62.2%), but the urea release rate was considerably slower. The addition of PVA and CA further inhibited the release rate. Importantly, the controlled release ability of CRF was demonstrated in carrot growth tests. The sustained release maintained high soil nitrogen content, thereby suppressing the growth of carrots sensitive to excess nitrogen. The final soil analysis results also supported these results, which paradoxically confirmed the excellent controlled release ability of CRF compared to conventional elements that are rapidly released. The fabricated CaAlg-based CRF shows great potential as an effective and environmentally friendly platform for regulating nitrogen supply in agricultural fields.

This study investigates the thermal comfort properties of synthetic fibers (polyester, nylon, acrylic) and their blends with cotton in three knitted structures: single jersey, single pique, and honeycomb. The air permeability, thermal conductivity, thermal resistance, and water vapor permeability of the fabrics were systematically evaluated. Results indicate that 100% polyester single jersey fabrics exhibit superior air permeability and water vapor permeability, making them ideal for sportswear. Nylon–cotton blends demonstrate high elasticity and moderate air permeability, suitable for lightweight and durable outdoor gear. Acrylic–cotton blends show the highest thermal resistance and a lower air permeability, making them ideal for cold-weather clothing. Blending synthetic fibers with cotton improves the balance of thermal comfort properties though it slightly reduces air permeability and thermal conductivity. Among the structures, single jersey consistently outperforms single pique and honeycomb in terms of thermal comfort. These findings provide valuable insights for selecting fibers and structures tailored to specific applications, such as sportswear, outdoor gear, and cold-weather clothing.

The rapid evolution of microelectronics and 5G communication technologies has accelerated the push toward higher integration density and device miniaturization in semiconductor and integrated circuit (IC) systems. Hence, ultra-low-dielectric interlayer materials have become increasingly critical due to their vital role in minimizing signal delay, transmission loss, and electromagnetic crosstalk in high-frequency applications. Among the organic dielectrics, aromatic polyimides (PIs) are regarded as high-performance materials due to their outstanding thermal stability (typically > 450 °C), excellent mechanical strength, chemical resistance, and electrical insulation. However, at a high frequency of 10 GHz, conventional PIs typically exhibit dielectric constants (D_k) and dielectric losses (D_f) of 3.1–3.5 and 0.008–0.02, respectively, which exceed the threshold (D_k < 2.7, D_f < 0.003) required for next-generation ultrafast communication systems. This limitation has spurred intensive research into strategies for intrinsically lowering both the D_k and D_f values of PIs. After introducing the fundamental principles governing the dielectric properties of PIs, the present review highlights recent progress in the molecular design of low-dielectric PIs by incorporating various functional groups, including fluorinated moieties, ester and ether linkages, bulky and non-planar substituents, and aliphatic segments. The effects of these structural modifications on the frequency-dependent dielectric responses and physicochemical properties are systematically analyzed, with an emphasis on elucidating the structure–property relationships that govern the permittivity and dissipation factor. This comprehensive and in-depth exploration of low-dielectric PIs is expected to serve as a fundamental theoretical foundation and valuable empirical reference for guiding the future development of high-performance, next-generation dielectric materials.

This study focuses on extracting natural colorants from the bark of Bridelia micrantha (SBBM) using a solvent extraction method with a magnetic stirrer under different operating conditions. The dyeing potential of the colorants obtained was evaluated by coloring vegetable-tanned leather alone and in combination with mordants at different dyeing conditions using Response Surface Methodology (RSM) with Box–Behnken Design. The properties of extracted dyes were analyzed for absorbance, functional groups, particle size distribution, and zeta potential. The dyed leather samples were evaluated for color strength, coordination, fastness, antibacterial activity, and physical–chemical properties. The results indicate that RSM effectively identified optimal conditions for extraction and dyeing processes with the coefficient of determination (R²) values of 0.9902 and 0.9909, respectively. Maximum absorbance of natural dye (3.88) was achieved at 89 °C, 67 min, and 0.1 g/mL SBBM-to-solvent ratio with a high combined desirability of 1.00. The absorbance analysis showed a peak for flavonoids, tannins, and phenolic acids. Further, Fourier-transform infrared spectroscopy characterized the presence of flavonoids, tannins, terpenoids, carotenoids, and phenolic acids. The optimum dyeing conditions were 40 °C, 4 h, and 25% colorant concentration, resulting in a maximum color strength of 4.45 with a desirability value of 1.00. Various shades and respectable color fastness of dyed samples were observed. Therefore, the eco-friendly natural dye extracted from the SBBM can be prominent for dyeing vegetable-tanned leather to sustain the leather value chain.

This study presents the development and evaluation of a bilayer hydrogel film designed for controlled drug delivery in wound dressing applications. The outer layer, composed of chitosan and glycerol, exhibited excellent water resistance, flexibility, and favorable moisture-handling properties, including high water vapor permeability and moisture absorption, which are critical factors for maintaining an optimal wound environment. The inner drug-loaded layer, formulated with carrageenan and loaded with either free turmeric or turmeric–β-cyclodextrin inclusion complex (TCD), served as the drug reservoir. Films incorporating TCD exhibited significantly enhanced turmeric solubility and drug release efficiency compared to those containing uncomplexed turmeric. Among the tested formulations, CS-TCD1, which featured a thinner drug-loaded layer, achieved the highest performance, with approximately 68% cumulative release over four days. While the release kinetics showed a strong correlation with the Higuchi kinetic model (R² = 0.9927), further analysis using the Akaike Information Criterion (AIC) and the Korsmeyer–Peppas model indicated an anomalous (non-Fickian) transport mechanism, governed by both diffusion and matrix swelling or erosion. These results highlight the importance of matrix architecture and drug solubilization strategies in the design of hydrogel-based drug delivery systems for wound care.

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To address the global challenge of fossil fuel consumption, a self-supporting supercapacitor electrode material was successfully fabricated to enable efficient utilization of renewable energy. In this study, lignin/polyacrylonitrile (PAN) carbon nanofibers (LCNFs), prepared via electrospinning, served as a conductive scaffold and growth substrate. This enabled the in situ growth of NiCo₂O₄ and CeO₂, co-constructing a composite electrode material (denoted as CeO₂/NiCo₂O₄@LCNFs) characterized by a petal-like nanosheet architecture. Results indicate that, compared to LCNFs, this uniquely structured composite enhances the exposure of active sites and facilitates charge and ion transport, thereby leading to significantly improved electrochemical performance. Furthermore, the influence of varying Ce content on the morphology, structure, and electrochemical properties of the composite was investigated. The CeO₂/NiCo₂O₄@LCNFs composite exhibited optimal morphology and electrochemical properties when the Ce addition amount was 0.5 mmol. It delivered a specific capacitance of 643.6 F g^-1 (at 0.5 A g^-1) and maintained a capacitance retention of 82.07% after 5000 cycles at 5 A g^-1. These results demonstrate the promising application potential of this electrode material and offer new perspectives for the development of novel electrode materials.

The proliferation of Internet of Things (IoT) technologies has driven widespread adoption of textile-integrated wearable electronics, with research advancements in piezoelectric nanogenerator systems demonstrating remarkable breakthroughs and transformative application prospects. This study fabricated high-performance piezoelectric nanofiber yarns via material optimization and textile engineering strategies to address the power constraints and seamless integration challenges in wearable electronics, while enabling biomechanical energy harvesting and continuous motion monitoring capabilities. Piezoelectric nanoyarns were prepared by introducing dopamine (DA)-modified barium titanate (BTO) nanoparticles, conjugated with polyvinylidene fluoride (PVDF) for electrostatic spinning, followed by coaxial interlocked nanostructures obtained by hydrothermal growth of a layer of zinc oxide (ZnO) nanowires on the surface of piezoelectric yarns, which enhanced the structural versatility of PVDF-based materials from two-dimensional to three-dimensional. The piezoelectric nanoyarns are characterized by high knittability and easy integration. By stitching them onto fabrics, they can achieve a high-performance voltage output of 3.2 V under the pressure applied by human body movement and sensitively monitor various forms of motion, providing innovative solutions for energy self-sufficiency and motion monitoring in the field of smart wearable, which will vigorously promote the expansion of the piezoelectric yarns in the application fields of action recognition and motion tracking, healthcare monitoring, pressure detection and tactile sensing. It serves as a powerful impetus for expanding the use of piezoelectric yarns in motion recognition and tracking, healthcare monitoring, pressure detection, and tactile sensing applications.

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In this research, an amphiphilic sodium alginate (SSA) was prepared by grafting styrene (St) onto sodium alginate (SA) to serve as a dispersant for preparing copper phthalocyanine (CuPc) pigment dispersion (SSA-CuPc). The results indicated that SSA exhibited optimal dispersibility for CuPc at 20% dosage. Compared to SA, the SSA-CuPc particle size was reduced by 63.61%, zeta potential from − 15.30 mV to − 29.16 mV. FT-IR, XPS, and TG analyses confirmed the effective binding of SSA on CuPc surface. The SSA-CuPc dispersion displayed excellent stability and compatibility in SA solution, with stability R value decreased to 5.66%. The SSA-CuPc was incorporated into SA spinning solution to fabricate dope-dyed SA fibers by wet spinning. Rheological tests revealed enhanced compatibility between SSA-CuPc and SA matrix, favorable for wet-spinning processing. Mechanical tests indicated a 35.33% improvement in elongation at break for dope-dyed SA fibers compared to original SA fibers. SEM, FT-IR, and TG analyses further verified the uniform distribution and stable existence of SSA-CuPc in SA fibers.

This research investigates the mechanical and thermal properties of fiber-reinforced polyester composites incorporating silane-treated fibers and granite dust fillers. The fatigue, creep, thermal conductivity, and water absorption properties were evaluated to determine the influence of reinforcement and filler content on composite performance. Fatigue test results indicate that specimen PPG2, with 2 vol.% granite dust, exhibited the highest fatigue resistance, with load values of 24,711 N, 21,711 N, and 18,741 N at 25%, 50%, and 75% of UTS, respectively. This improvement is attributed to the optimal combination of fiber reinforcement and filler content, ensuring effective stress distribution and superior fiber-matrix bonding. In contrast, specimen PPG3, with 4 vol.% granite dust, demonstrated the best performance in creep resistance, thermal insulation, and water absorption properties. The creep strain values for PPG3 were recorded as 0.0059, 0.0068, and 0.0084 at 5000, 10,000, and 15,000 s, respectively, indicating superior resistance to time-dependent deformation due to increased filler content acting as rigid barriers within the matrix. Additionally, PPG3 exhibited the lowest thermal conductivity of 0.24 W/mK, highlighting its excellent insulating properties, as the presence of higher filler content disrupted heat transfer pathways. Water absorption values for PPG3 reached 0.042%, the highest among the tested specimens, which is associated with the hydrophilic nature of granite dust particles at higher filler concentrations. The scanning electron microscope (SEM) analysis further confirmed the structural integrity of the composites, with PPG2 displaying well-dispersed fillers and strong adhesion at the fiber-matrix interface, while PPG3 exhibited slight delamination due to increased filler content. These findings underscore the importance of optimizing reinforcement and filler content to enhance the fatigue and thermal properties of polyester composites for structural and industrial applications.

This study explores the dynamic behavior of macro-fiber composite (MFC) under varying voltage and curvature conditions, aiming to optimize its maximum displacement. We identified a direct relationship between applied voltage and displacement, with higher voltages leading to increased displacements. Concurrently, the natural frequency decreased as effective stiffness and electromechanical coupling changed. To measure maximum displacement, a novel sweep method was introduced and validated, demonstrating a low error rate and offering a reliable alternative to traditional techniques, particularly for curved or irregular structures. Further, the study revealed that curvature significantly impacts both the natural frequency and maximum displacement of MFCs. A critical curvature point was identified, where displacement behavior shifted, providing essential insights for optimizing MFC design and application. These findings contribute to a deeper understanding of MFC dynamics and open new avenues for applying the sweep method to other piezoelectric materials and complex geometries. This research sets the stage for future studies aimed at refining the sweep method for more precise and efficient use in advanced engineering applications.