Search Results (432)

The growing demand for sustainable materials has led to increased interest in biodegradable polymer fibers and nonwoven mats due to their eco-friendly characteristics and potential to reduce plastic pollution. This review highlights how mechanical properties influence the performance and suitability of biodegradable polymer fibers across diverse applications. This covers synthetic polymers such as polylactic acid (PLA), polyhydroxyalkanoates (PHAs), polycaprolactone (PCL), polyglycolic acid (PGA), and polyvinyl alcohol (PVA), as well as natural polymers including chitosan, collagen, cellulose, alginate, silk fibroin, and starch-based polymers. A range of fiber production methods is discussed, including electrospinning, centrifugal spinning, spunbonding, melt blowing, melt spinning, and wet spinning, with attention to how each technique influences tensile strength, elongation, and modulus. The review also addresses advances in composite fibers, nanoparticle incorporation, crosslinking methods, and post-processing strategies that improve mechanical behavior. In addition, mechanical testing techniques such as tensile test machine, atomic force microscopy, and dynamic mechanical analysis are examined to show how fabrication parameters influence fiber performance. This review examines the mechanical performance of biodegradable polymer fibers and fibrous mats, emphasizing their potential as sustainable alternatives to conventional materials in applications such as tissue engineering, drug delivery, medical implants, wound dressings, packaging, and filtration. Full article

Hydrogels, especially Polyvinyl alcohols, have received extensive attention as alternative materials for articular cartilage. Aiming at the problems such as low strength and poor toughness of polyvinyl alcohol hydrogels in practical applications, an enhancement and modification strategy is proposed. Sodium alginate fibers were introduced into polyvinyl alcohol hydrogel network through physical blending and freezing/thawing methods. The prepared composite hydrogels exhibited a three-dimensional porous network structure similar to that of human articular cartilage. The mechanical and tribological properties of hydrogels have been significantly improved, due to the multiple hydrogen bonding interaction between sodium alginate fibers and polyvinyl alcohol. Most importantly, under a load of 2 N, the friction coefficient of the PVA/0.4SA hydrogel can remain stable at 0.02 when lubricated in PBS buffer for 1 h. This work provides a novel design strategy for the development of high-performance polyvinyl alcohol hydrogels. Full article

This study investigates the synergistic modification of cement–soil using waste brick powder (WBP) and polyvinyl alcohol (PVA) fibers to address the growing demand for sustainable construction materials and recycling of demolition waste. An orthogonal experimental design was employed with 5% WBP (by mass) and PVA fiber content (0–1%), evaluating mechanical properties based on unconfined compressive strength (UCS) and splitting tensile strength (STS) and microstructure via scanning electron microscopy (SEM) across 3–28 days of curing. The results demonstrate that 0.75% PVA optimizes performance, enhancing UCS by 28.3% (6.87 MPa) and STS by 34.6% (0.93 MPa) at 28 days compared to unmodified cement–soil. SEM analysis revealed that PVA fibers bridged microcracks, suppressing propagation, while WBP triggered pozzolanic reactions to densify the matrix. This dual mechanism concurrently improves mechanical durability and valorizes construction waste, offering a pathway to reduce reliance on virgin materials. This study establishes empirically validated mix ratios for eco-efficient cement–soil composites, advancing scalable solutions for low-carbon geotechnical applications. By aligning material innovation with circular economy principles, this work directly supports global de-carbonization targets in the construction sector. Full article

This paper evaluates the synergistic effect of polyvinyl alcohol (PVA) fibers and nanosilica (nS) on the mechanical behavior and deformation properties of engineered cementitious composites (ECCs). ECCs have gained a reputation for high ductility, crack control, and strain-hardening behavior. Nevertheless, the next step is to improve their performance even more through nano-modification and fine-tuning of fiber dosage—one of the major research directions. In the experiment, six types of ECC mixtures were made by maintaining constant PVA fiber content (0.5, 1.0, 1.5, and 2.0%), while the nanosilica contents were varied (0, 1, 2, 3, and 5%). Stress–strain tests carried out in the form of compression, together with unrestrained shrinkage measurement, were conducted to test strength, strain capacity, and resistance to deformation, which was highest at 80 MPa, recorded in the concrete with 2% nS and 0.5% PVA. On the other hand, the mixture of 1.5% PVA and 3% nS had the highest strain result of 2750 µm/m, which indicates higher ductility. This is seen to be influenced by refined microstructures, improved fiber dispersion, and better fiber–matrix interfacial bonding through nS. In addition to these mechanical modifications, the use of nanosilica, obtained from industrial byproducts, provided the possibility to partially replace Portland cement, resulting in a decrease in the amount of CO₂ emissions. In addition, the enhanced crack resistance implies higher durability and reduced long-term maintenance. Such results demonstrate that optimized ECC compositions, including nS and PVA, offer high performance in terms of strength and flexibility as well as contribute to the sustainability goals—features that will define future eco-efficient infrastructure. Full article

Achieving carbon neutrality requires not only reducing CO₂ emissions but also capturing atmospheric CO₂. Direct air capture (DAC) using amine-based adsorbents has emerged as a promising approach. In this study, we developed amine-epoxy/poly(vinyl alcohol) (AE/PVA) nanofibers via electrospinning and in situ thermal polymerization. PVA was incorporated to enhance spinnability, and B-staging of AE enabled fiber formation without inline heating. We systematically investigated the effects of electrospinning parameters, epoxy-to-amine ratios (E/A), and the degree of PVA saponification on CO₂ adsorption performance. Thinner fibers, obtained by adjusting spinning conditions, exhibited faster adsorption kinetics due to increased surface area. Varying the E/A revealed a trade-off between adsorption capacity and low-temperature desorption efficiency, with secondary amines offering a balanced performance. Additionally, highly saponified PVA improved thermal durability by minimizing side reactions with amines. These findings highlight the importance of optimizing fiber morphology, chemical composition, and polymer properties to enhance the performance and stability of AE/PVA nanofibers for DAC applications. Full article

Since airborne microplastics (AMPs) are a recent and unexplored field of study, there are several unresolved issues regarding their effects on plants. The accumulating potential of AMPs and their effect on the biochemical parameters of ten different plant species in an Indian city environment were assessed. The four types of AMPs deposited in the phyllosphere—fragment (30.76%), film (28.95%), fiber (22.61%), and pellet (17.68%)—were examined using stereomicroscopy and fluorescence microscopy. The air pollution tolerance index (APTI) was determined, and other biochemical parameters such as proline, phenol, malondialdehyde, carotenoids, superoxide dismutase, catalase, and peroxidase were also measured. The findings showed that in the case of polymers type, PE (30%) was more abundant than others, followed by PET (17%), PP (15%), PVC (13%), PVA (10%), PS (7%), ABS (5%), and PMMA (3%). Clerodendrum infortunatum L., Calotropis procera (Aiton) W.T. Aiton, and Mangifera indica L. all showed a strong APTI and also exhibited significantly higher amounts of AMP accumulation. Principal component analysis showed a stronger association between phyllospheric AMPs and biochemical parameters. Additionally, the correlation analysis revealed that the presence of accumulated AMPs may significantly influence the biochemical parameters of the plants. Thus, it can be concluded that the different plant species are uniquely specialized in AMP accumulation, which is significantly impacted by the plants’ APTI as well as other biochemical parameters. Full article

This study presents the development and characterization of electrospun nanofibers composed of polyvinyl alcohol (PVA) and natural beeswax (BW). A stable emulsion containing 9 wt% PVA and 5 wt% BW was successfully formulated and electrospun. The effects of beeswax incorporation on solution properties-viscosity, conductivity, and surface tension—were systematically evaluated. Electrospinning was performed at 30 kV and a working distance of 14.5 cm, yielding nanofibers with diameters between 125 and 425 nm. Scanning electron microscopy (SEM) revealed increased surface roughness and diameter variability in PVA/BW fibers compared to the PVA. Fourier transform infrared spectroscopy (FTIR) confirmed physical incorporation of BW without evidence of chemical bonding. Thermogravimetric and differential scanning calorimetry analyses (TGA/DSC) demonstrated altered behavior and an expanded profile of temperature transitions due to the waxy components. The solubility test of the nanofiber mat in saline indicated that BW slows dissolution and improves the structural integrity of the fibers. This study demonstrates, for the first time, the incorporation of beeswax into electrospun PVA nanofibers with improved structural and thermal properties, indicating potential for further exploration in biomedical material design. Full article

The bond interface is the weakest part of the repair system, and its performance is a key factor impacting the repair effectiveness of damaged concrete constructions. However, the research on the damage law and the mechanism of repair of the bonded interface in the cold region marine environment is not in-depth. In this study, the influence of polyvinyl alcohol (PVA) fibers and crystalline admixtures (CAs) on the mechanical properties and volumetric deformation performance of cementitious repair materials was researched. Furthermore, the deterioration patterns of the bond strength and chloride ion diffusion characteristics of the repair interface under the coupling of seawater-freeze-thaw cycles were investigated. Combined with the composition, micro-morphology, and micro-hardness of hydration products before and after erosion, the damage mechanism of the repaired bonding interface was revealed. The results indicate that the synergistic use of PVA fibers and CAs can significantly improve the compressive strength, bond strength and volume stability of the repair materials. The compressive strength and 40° shear strength of S0.6CA at 28 d were 101.7 MPa and 45.95 MPa, respectively. Under the seawater-freeze-thaw cycle action, the relationship between the contents of free and bound chloride ions in the bonded interface can be better fitted by the Langmuir equation. The deterioration process of the bonding interface and the penetration rate of chloride ions can be effectively delayed by PVA fiber and CAs. After 700 seawater-freeze-thaw cycles, the loss rates of bond strength and chloride diffusion coefficient of S0.6CA were reduced by 26.34% and 52.5%, respectively, compared with S0. Full article

Bio-nanocomposites based on poly (vinyl alcohol) (PVA) and cellulosic nanostructures are favorable for active food packaging applications. The current study systematically investigates the mechanical properties, gas permeation, and swelling parameters of PVA composites with cellulose nanocrystals (CNC) or nano lignocellulose (NLC) fibers. Alterations in these macroscopic properties, which are critical for food packaging applications, are correlated with structural information at the molecular level. Strong interactions between the fillers and polymer host matrix were observed, while the PVA crystallinity exhibited a maximum at ~1% loading. Finally, the orientation of the PVA nanocrystals in the uniaxially stretched samples was found to depend non-monotonically on the CNC loading and draw ratio. Concerning the macroscopic properties of the composites, the swelling properties were reduced for the D1 food simulant, while for water, a considerable decrease was observed only when high NLC loadings were involved. Furthermore, although the water vapor transmission rates are roughly similar for all samples, the CO₂, N₂, and O₂ gas permeabilities are low, exhibiting further decrease in the 1% and 1–5% loading for CNC and NLC composites, respectively. The mechanical properties were considerably altered as a consequence of the good dispersion of the filler, increased crystallinity of the polymer matrix, and morphology of the filler. Thus, up to ~50%/~170% enhancement of the Young’s modulus and up to ~20%/~50% enhancement of the tensile strength are observed for the CNC/NLC composites. Interestingly, the elongation at break is also increased by ~20% for CNC composites, while it is reduced by ~40% for the NLC composites, signifying the favorable/unfavorable interactions of cellulose/lignin with the matrix. Full article

To address the demands for resource utilization of Yellow River sediment and the durability requirements of engineering materials in cold regions, this study systematically investigates the mechanisms affecting the frost resistance of slag-Yellow River sediment geopolymers through the incorporation of mineral admixtures (silica fume and metakaolin) and fibers (steel fiber and PVA fiber). Through 400 freeze-thaw cycles combined with microscopic characterization techniques such as SEM, XRD, and MIP, the results indicate that the group with 20% silica fume content (SF20) exhibited optimal frost resistance, showing a 19.9% increase in compressive strength after 400 freeze-thaw cycles. The high pozzolanic reactivity of SiO₂ in SF20 promoted continuous secondary gel formation, producing low C/S ratio C-(A)-S-H gels and increasing the gel pore content from 24% to 27%, thereby refining the pore structure. Due to their high elastic deformation capacity (6.5% elongation rate), PVA fibers effectively mitigate frost heave stress. At the same dosage, the compressive strength loss rate (6.18%) and splitting tensile strength loss rate (21.79%) of the PVA fiber-reinforced group were significantly lower than those of the steel fiber-reinforced group (9.03% and 27.81%, respectively). During the freeze-thaw process, the matrix pore structure exhibited a typical two-stage evolution characteristic of “refinement followed by coarsening”: In the initial stage (0–100 cycles), secondary hydration products from mineral admixtures filled pores, reducing the proportion of macropores by 5–7% and enhancing matrix densification; In the later stage (100–400 cycles), due to frost heave pressure and differences in thermal expansion coefficients between matrix phases (e.g., C-(A)-S-H gel and fibers), interfacial microcracks propagated, causing the proportion of macropores to increase back to 35–37%. This study reveals the synergistic interaction between mineral admixtures and fibers in enhancing freeze–thaw performance. It provides theoretical support for the high-value application of Yellow River sediment in F400-grade geopolymer composites. The findings have significant implications for infrastructure in cold regions, including subgrade materials, hydraulic structures, and related engineering applications. Full article

Predicting the flexural behavior of fiber-reinforced ultra-high-performance concrete (UHPC) remains a significant challenge due to the complex interactions among numerous mix design parameters. This study presents a machine learning-based framework aimed at accurately estimating the modulus of rupture (MOR) of UHPC. A comprehensive dataset comprising 566 distinct mixtures, characterized by 41 compositional and fiber-related variables, was compiled. Seven regression models were trained and evaluated, with Random Forest, Extremely Randomized Trees, and XGBoost yielding coefficients of determination (R²) exceeding 0.84 on the test set. Feature importance was quantified using Shapley values, while partial dependence plots (PDPs) were employed to visualize both individual parameter effects and key interactions, notably between fiber factor, water-to-binder ratio, maximum aggregate size, and matrix compressive strength. To validate the predictive performance of the machine learning models, an independent experimental campaign was carried out comprising 26 UHPC mixtures designed with varying binder compositions—including supplementary cementitious materials such as fly ash, ground recycled glass, and calcium carbonate—and reinforced with mono-fiber (straight steel, hooked steel, and PVA) and hybrid-fiber systems. The best-performing models were integrated into a hybrid neural network, which achieved a validation accuracy of R² = 0.951 against this diverse experimental dataset, demonstrating robust generalizability across both material and reinforcement variations. The proposed framework offers a robust predictive tool to support the design of more sustainable UHPC formulations incorporating supplementary cementitious materials without compromising flexural performance. Full article

Engineered cementitious composites (ECCs), known for their superior ductility and strain-hardening behavior compared to conventional concrete, have been predominantly studied with polyvinyl alcohol (PVA) fibers. However, the potential economic and technical advantages of incorporating steel fibers into ECCs have been largely overlooked in the literature. This study investigates the mechanical performance of ECC reinforced with different types of steel fibers, including straight, twisted, hooked, and hybrid fibers of different lengths, as compared to PVA. The inclusion of various supplementary cementitious materials (SCMs) such as slag and fly ash with each type of steel fiber was also considered at a constant fiber volume fraction of 2%. The mechanical properties were assessed through compressive strength, splitting tensile strength, and four-point flexural tests along with calculations of toughness, ductility, and energy absorption capacity indices. This study compares the mechanical properties of different ECC compositions, revealing that ECCs with hybrid steel fibers (short and long) achieved more than twice the tensile strength, 12.7% higher toughness, and 36.4% greater energy absorption capacity compared to ECCs with PVA fibers, while exhibiting similar multiple micro-cracking behavior at failure. The findings highlight the importance of fiber type and distribution in enhancing an ECC’s mechanical properties, providing valuable insights for developing more cost-effective and resilient construction. Full article

To mitigate ecological damage from excessive natural aggregate extraction, this study developed an eco-friendly concrete using dune sand and steel slag as natural aggregates, enhanced with polyvinyl alcohol (PVA) fibers. Through orthogonal testing, the effects of the dune sand replacement ratio, steel slag replacement ratio, PVA fiber length, and PVA fiber content on concrete workability and mechanical properties were analyzed. The results show that slump exceeded 120 mm (meeting engineering requirements) in mixes except that with 40% dune sand, 60% steel slag, 18 mm PVA fiber length, and 0.4% PVA fiber content; 50% steel slag replacement significantly improved mechanical properties, yielding a 21.2% increase in 28 d compressive strength when replacement increased from 30% to 50%; 20% dune sand replacement for river sand is optimal; and while increased PVA content enhanced splitting tensile and flexural strengths, both its length and content should not exceed 9 mm and 0.3%, respectively. The concrete delivers acceptable performance while providing dual environmental benefits: reduced aggregate consumption pressure and achieved high-value-added dune sand–steel slag utilization. Full article

This study presents the development and comprehensive characterization of biopolymer-based nanofibrous composites composed of polyvinyl alcohol (PVA), chitosan (CS), boric acid (BA), and a natural antifungal agent natamycin (NAT), designed for therapeutic applications. A dual-layer 3D-fiber composite (PVA/CS/BA_PVA/NAT) was successfully fabricated using a layer-by-layer 3D bioprinting technique and electro-spinning, integrating BA into the core matrix and NAT into the outer layer. Mechanical tests revealed a significantly improved elastic modulus of 763.04 ± 14.54 MPa and the highest ultimate tensile stress (50.45 ± 2.58 MPa) among all samples. Despite a moderate strain at break (11.77 ± 0.49%), the composite preserved sufficient elasticity suitable for biological interfaces. Morphological assessment via SEM confirmed the successful deposition of continuous and bead-free nanofibers, with controlled fiber alignment and reduced average fiber diameters, especially in the BA-incorporated structure. The dual-layered system displayed enhanced uniformity and structural coherence. The drug release analysis demonstrated sustained NAT delivery over a 90 min period. Kinetic modeling showed a high correlation with the Korsmeyer–Peppas model (R² > 0.99), suggesting diffusion-controlled release, supported by the Korsmeyer–Peppas model’s Fickian diffusion exponent. In contrast, zero- and first-order models exhibited weaker fits, underscoring the relevance of a matrix-based release mechanism governed by the layered configuration. Crucially, antifungal assays against Candida albicans revealed substantial bioactivity. The PVA/CS/BA_PVA/NAT formulation achieved the largest inhibition zone (1.64 ± 0.13 cm), significantly outperforming single-layer controls such as PVA/CS/BA (1.25 ± 0.08 cm) and PVA/CS_PVA/NAT (1.43 ± 0.08 cm), while neat PVA exhibited no inhibition. These results confirm the synergistic antifungal efficacy of BA and NAT within the dual-layer structure. Together, these findings highlight the potential of the 3D-printed PVA/CS/BA_PVA/NAT composite as a mechanically robust, morphologically optimized, and bioactive platform for antifungal therapy and wound-healing applications. Full article

The electrospinning technique can produce multifunctional polymeric devices by forming solid fibers from polymer solutions under a high-voltage electric field. Variations such as concentric needles yield core/shell fibers. This study evaluates the effects of applied voltage (12.5–20 kV) and tip-to-collector distance (12.5–20 cm) on the morphology and thermochemical behavior of PLGA/PVA fibers made by coaxial electrospinning compared with casting-produced membranes and monolithic fibers. Optimal coaxial fibers (597 ± 90 nm diameter) were produced at 15 cm/12.5 kV, exhibiting a well-defined core/shell structure (PVA core: ~100 nm; PLGA shell: ~50 nm) confirmed by laser scanning confocal (core solution labeled with fluorescein) and TEM. FTIR and TGA demonstrated nearly complete solvent removal in electrospun samples versus ~10% solvent retention in cast films. XRD analysis indicated that cast films (PLGAff) exhibited minimal crystallinity (Xc ≈ 0.1%), while electrospun PLGA (PLGAe) showed cold crystallization and higher crystallinity (Tcc ≈ 90.6 °C; Xc ≈ 2.45%). DSC detected two different Tg (≈43.2 °C and 52.8 °C) in the coaxial fibers, confirming distinct polymer domains with interfacial interactions. These results establish precise processing/structure relationships for defect-free coaxial fibers and provide fundamental design principles for hybrid systems in controlled drug delivery and tissue engineering applications. Full article