Fibers and Polymers最新文献

Polyethylene terephthalate (PET) is a versatile polymer widely used in textiles because of its chemical stability, mechanical strength, and ease of processing. However, the increasing consumption of PET, particularly in the textile industry, has led to significant environmental concerns owing to its resistance to degradation. To address these issues, chemical recycling methods, particularly glycolysis, have attracted attention for depolymerizing PET into valuable monomers for repolymerization. This review focuses on recent advances in catalysts for PET glycolysis, with special emphasis on their application in textile recycling. We categorized the catalysts into homogeneous and heterogeneous types and discussed their effectiveness in reducing the reaction temperatures and times, thereby decreasing energy consumption and operational costs. Although homogeneous catalysts achieved efficient depolymerization at lower temperatures, their post-reaction separation and purification steps remain challenging and costly. In contrast, heterogeneous catalysts offer simpler separation processes but require significant energy input. Research on the application of glycolytic catalysts in fiber recycling was also highlighted, considering the substantial use of PET in the textile industry. Finally, we suggested future research directions for developing cost-effective and sustainable catalysts that are applicable to PET fibers with the aim of enhancing the efficiency and environmental sustainability of PET recycling processes.

The present study revealed the effect of alkali (sodium hydroxide, NaOH) and graphene oxide (GO) treatment on the mechanical and thermal characteristics of the raw pineapple leaf fiber (PLF). This was carried out using different concentrations of NaOH (2, 4, 6, 8 and 10% at variable time of 2, 4, 6, 8 and 10 h) and GO (0.5 mg/mL, 0.75 mg/ mL, 1 mg/ mL, 1.25 mg/ mL for 30 min) to determine the optimal treatment conditions. The results showed substantial increase in average tensile strength and thermal stability of the fibers post-treatment. Specifically, a 1 mg/ mL concentration of GO exhibited the highest mean strength, enhancing the fiber's structural integrity. Both raw and treated fiber samples were analysed by different characterization techniques. Results of the FTIR, SEM, DSC and TGA analysis confirmed the removal of impurities and the successful addition of NaOH and GO into the fiber matrix. These findings suggest that chemical modification of PLF can yield high-performance materials. This study presents a novel method to improving the characteristics of natural fibers contributing to development of sustainable as well as the efficient composite materials.

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Textiles have broad application prospects in the fields of flexible sensors and intelligent wearable devices due to their excellent breathability, softness, and structural elasticity. Piezoelectric sensors have become a hot topic in the field of wearable applications due to their ability to perform long-term sensing and detection. This article enhances the performance of composite materials by adding polydopamine (PDA) to improve the interaction between polymer matrix and nanofillers, and optimizes the composite nanofiber membrane synthesized by electrospinning polyvinylidene fluoride (PVDF) and barium titanate (BTO) nanoparticles. The content of β-phase in the optimized PVDF–BTO nanofiber membrane reached 81.58%. In bending mode, its open-circuit voltage reaches 10.36 V. Under vertical pressure conditions, when the pressure is 2.914N, the voltage of the sensor reaches 13.35 V, and the sensitivity of the nanofiber membrane is 2.918VN⁻¹, with a good linear relationship. This flexible piezoelectric sensor demonstrates various potential applications, including facial recognition, speech recognition, motion monitoring, etc. This research provides a simple and convenient way to develop high-performance self-powered wearable electronic products.

As the use of antibiotics such as tetracyclines has increased, their presence in water has also risen, making their removal from water sources increasingly important. In this study, a film containing polyvinyl alcohol (PVA), cotton fiber, and carbonyl iron (PVA–CF/CI) was prepared, and its use as an adsorbent material for removing tetracycline from water was investigated. The characterization of the PVA–CF/CI film was carried out using SEM–EDAX and FTIR analyses. It was observed that the addition of carbonyl iron to the PVA film significantly increased tetracycline removal. The adsorption kinetic of tetracycline was found to follow pseudo-second-order model, and the adsorption isotherm model was best described by the Langmuir isotherm model. Tetracycline removal reached 90.8% at pH 3 and 1 g film dose. The q_max obtained with the PVA–CF/CI film containing carbonyl iron was 3.8 times higher than that obtained with the PVA film alone. As a result, while the addition of cotton to the films was not significantly effective, the addition of carbonyl iron was found to significantly enhance tetracycline removal. Additionally, it is possible to produce a more economical and less toxic film polymer by using PVA, cotton, and carbonyl iron.

Enhancing vehicle crashworthiness is critical for improving passenger safety during collisions. Subsequently, this research seeks to explore both the deformation characteristics and the crashworthiness behaviors of square tubes made from 3D-printed polylactic acid (PLA). For this reasons, three printing parameters are examined, each at four different levels: infill pattern structure (gyroid, honeycomb, Schwarz P, and Schwarz D), infill density (5, 10, 20, and 30%), and layer height (0.15, 0.20, 0.25, and 0.30 mm). The structures were exposed to quasi-static axial compression loading to assess their performance. During the testing of these tubes, data were systematically gathered on crashing load, absorbed energy, and displacement responses. In addition, the failure histories of each tube were accurately documented. The evaluation of crashworthiness involved the measurement of several critical indicators: the initial peak crash load (({F}_{text{ip}})), the total energy absorbed (U), the mean crash load (({F}_{text{m}})), the specific absorbed energy (SEA), and the crash force efficiency (CFE). To identify the optimal configuration, a multi-attribute decision-making (MADM) approach was employed. This analysis revealed that the combination of honeycomb pattern structure, 30% infill density, and a layer height of 0.20 mm (denoted as H30/0.20), which achieved ({F}_{text{ip}}), U, ({F}_{text{m}}), SEA, and CFE of 26.35 kN, 1440.73 J, 24.01 J/g, 33.54 kN, and 0.911, respectively, offered the best performance in terms of crashworthiness.

This study examines the effects of the coupling agent maleic anhydride-grafted polypropylene on the thermal and dielectric properties of areca–polypropylene composites. Test specimens of both uncoupled and coupled composites were prepared using injection molding methods in accordance with ASTM standards, with filler percentages ranging from 20 to 50%. Dielectric characteristics were evaluated across frequencies ranging from 10 Hz to 10 MHz and temperatures from 30 °C to 120 °C at 10 °C intervals. The results showed enhanced dielectric properties in the maleic anhydride-grafted polypropylene composites due to improved fibre dispersion and polarization mechanisms. These composites, with their high dielectric constants, have potential applications in gate dielectrics, actuators, sensors, and more. The morphology and chemical composition were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy, while thermogravimetric analysis and water diffusion coefficient tests confirmed the successful grafting of the coupling agent onto the fibres.

Tea polysaccharide (TP), as a naturally occurring bioactive polysaccharide derived from tea leaves, exhibits diverse pharmacological activities, which extensively utilized in healthcare products. However, previously reported applications did not include wound repair until now. In this study, TPs isolated from Tibetan tea was compound with bacterial cellulose (BC) via a novel membrane–liquid interface (MLI) culture resulted in obtained a novel TP-based dressing. The results of SEM and AFM confirmed successful attachment of TPs onto the surface of BC fibers. The obtained TP/BC composite exhibited robust thermal stability, excellent water absorption, acceptable water retention, and improved mechanical properties. The introduction of TP also conferred the dressing notable antioxidant properties (DPPH clearance rate was up to 85%), acceptable antibacterial properties (the antibacterial rate against S. aureus and E. coli were above 80%), and potent anti-inflammatory activity (the secretion of pro-inflammatory factor TNF-α was inhibited, while the secretion of anti-inflammatory factor TGF-β was promoted). Furthermore, the TP/BC composite exhibited improved cytocompatibility to promote NIH3T3 cells proliferation and spread compared with BC. All results indicated that the obtained TP/BC composite has an enormous potential for wound dressing, and the application of TP will be broadened.

In the present study, we hypothesized that the presence of gallic acid as an additive antioxidant agent and alendronate can improve the osteogenic differentiation potency of human adipose mesenchymal stem cells, cultured on the scaffolds with fiber-microparticle structures. For this purpose, a combination of electrospinning and electrospraying techniques was employed to prepare a fiber-microparticle structure, composed of polycaprolactone (PCL)–alendronate (ALN) fibers/gallic acid-loaded chitosan nanoparticles (GNP) @ polyvinylpyrrolidone (PVP) microparticles. GNPs were fabricated by a cross-junction microfluidic device. By adjusting the gallic acid concentration, three types of GNPs were fabricated. The morphology of fabricated nanoparticles was quasi-sphere. %Loading efficiency increased by employing higher concentrations of gallic acid. According to dynamic light scattering results, the average hydrodynamic diameter of nanoparticles was between 213 and 217 nm. The impact of ALN concentration on the size and morphology of PCL electrospun scaffolds was separately investigated by SEM in which PCL/ALN 2.5% was selected for the next steps. The % porosity of all samples was around 62–68%. The release profile of ALN was slower than gallic acid. The % 1,1 diphenyl-2-picrylhydrazyl (DPPH) inhibition analysis showed that the presence of gallic acid could effectively improve the additive antioxidant properties of fabricated scaffolds. According to the MTT results, the presence of ALN could significantly improve the proliferation of human adipose mesenchymal stem cells. The alkaline phosphatase (ALP) activity and calcium deposition assessments on days 7, 14, and 21 and the evaluation of mRNA levels of ALP and osteopontin on days 7 and 14 confirmed the synergistic impact of gallic acid and ALN on osteogenic differentiation.

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A series of five azo dyes derived from the diazonium salt of 4-aminoantipyrine and α- and β-naphthols and naphthalenediol were synthesized, and their chemical structures were identified by spectral measurements such as UV, FT-IR, and NMR, as well as elemental analysis. The chemical descriptor parameters of the synthesized dyes were computed using the B3LYP/6-31G(d,p) level. The dyes were classified as disperse dyes and were used to dye polyester fibers at high temperature and pH 4.0–5.0, utilizing acetic acid, while dispersing agents were added to enhance the stability and dispersion of the dyes. The color fastness properties of the dyed fibers were tested, and their color strength, reflectance, and dye exhaustion were measured. Finally, a plausible mechanism for the dyeing process was suggested.

Oil spills and marine pollution caused by oil spills have a serious effect on environment and human life. The efficient removal of oils, petroleum-based products, and organic solvents from water is important for protecting the environment. Oil-absorbent nanofiber mats with high oleophilicity were prepared by electrospinning in the present work. Nylon 6,6 is chosen as a crystalline polymer with oleophilic hydrocarbon chains that are linked by hydrophilic functional amides. There has been little research into using electrospun Nylon 6,6 as an oil absorbent to remove oil from water. Two different organically modified montmorillonites (o-MMT, with trade names Tixogel VP and Cloisite 20A—C20A) are separately incorporated into Nylon 6,6 polymer to produce nanofiber mats with more oleophilic properties. To achieve efficient dispersion and exfoliation of organoclays in Nylon 6,6/formic acid solution, ultrasonication is applied for 30 min, followed by mixing for 24 h with a magnetic stirrer. After reaching a more homogenous solution, Nylon 6,6-organoclay nanofiber mats were then successfully electrospun by the electrospinning technique and characterized by using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and water contact angle measurement (WCA). The mechanical properties of the mats were also evaluated. The absorption behavior of the mats for motor oil and other domestic oils was investigated and the absorption capacity calculated in terms of weight gain. Differences in the absorption capacity of these three types of oil were found to be due to the surface tension of the solvents in the oil and viscosity. It has been found that the nanofibers produced have a very high oil absorption capacity in the case of a 2% loading of organoclay. These newly produced mats demonstrated excellent motor oil absorption of 60–80 times their own weight in motor oil. It can be concluded that these novel oil-absorbing materials are promising candidates for the treatment of wastewater containing oil.