Fibers and Polymers最新文献

Carbon dots (CDs), the subject of the Nobel Prize in chemistry in 2023, are promising materials for active food packaging with properties, such as antioxidant and antimicrobial activity, non-toxicity, and ultraviolet protection. Therefore, composite films containing CDs have been investigated for food packaging applications in recent years. However, as far as we know, limited studies have been carried out in which carbon dots are added to nanofibrous mats, which show superior properties such as high surface area-to-volume ratio compared to film structures. In this study, CDs were produced via hydrothermal carbonization from the waste material, the spent pumpkin. Aimed to develop and evaluate composite nanofibrous mats incorporating carbon dots (CDs) for active food packaging, specifically utilizing spent pumpkin-derived carbon dots (SPCDs) to enhance the functional properties of the packaging materials. The composite nanofibrous mats, fabricated from a blend of polyvinyl alcohol and carboxymethyl cellulose incorporating SPCDs, demonstrated low toxicity on chondrocyte and lung cell types, indicating their safety for food packaging applications. The inclusion of SPCDs enhanced the antioxidant activity provided inhibitory effects against E. coli and S. aureus, and improved the mechanical strength of the mats. Real food trials with walnut oils revealed that the mats effectively reduced lipid oxidation, thereby extending the product's shelf life. Additionally, the mats were fully biodegradable, decomposing completely in soil within 42 days. These results suggest that the novel composite nanofibrous mats have great potential for sustainable and active food packaging, offering a practical and comprehensive solution for the industry.

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Electrochromic devices (ECDs) have evolved significantly with advancements in electrochromic materials. Viologen-based ECDs, known for their tunable electrochromic properties, face challenges such as low cyclic lifetime and electrolyte leakage. This study introduces poly-APPV, a pendant viologen polymer exhibiting transmissive-to-black electrochromic switching. The polymer offers enhanced long-term stability and rapid switching times, effectively addressing these challenges. The synthesis of allyl viologen, [APPV][PF₆]₂, and poly-APPV is successfully characterized using ¹H-NMR, FT-IR, and GPC analyses. Cyclic voltammetry reveals diffusion-controlled redox reactions, while electrochemical impedance spectroscopy shows acceptable ionic conductivity of poly-APPV. Spectroelectrochemical studies indicate significant transmittance changes, with poly-APPV exhibiting a lower operating voltage and superior transmittance difference. Long-term stability tests confirm superior optical density and high coloration efficiency of poly-APPV. Overall, the pendant viologen polymer’s enhanced properties make it a promising material for electrochromic applications. These findings prove the benefits of polymerized viologens in enhancing electrochromic performances, offering valuable insights for developing next-generation electrochromic systems.

Spacer fabric (SF) as an ideal candidate for steam protective clothing, provides outstanding thermal insulation and moisture permeability owing to its sandwich structure. This study developed 14 spacer fabric systems (SFSs) and investigated the effects of 4 SF design parameters, including heat setting, spacer yarn fineness, feeding structure, and top layer structure, on thermal comfort. Furthermore, the quantitative relationship between thermal comfort and steam protective performance of SFSs was explored. The results demonstrated that thermal resistance (R_cf) and evaporative resistance (R_ef) of SFSs increased with the increasing of monofilament fineness, whereas increasing the fineness from 30 to 50 D had a negligible influence. The feeding structure displayed a greater impact on the thermal comfort than monofilament fineness, and the R_cf and R_ef showed the sequence of feeding structure I < II < III. SF heat setting and top layer structure minimally influence the R_cf and R_ef of SFSs. The R_ef was positively correlated with the time to second-degree burn, and negatively correlated with absorbed energy during exposure and total absorbed energy, both strongly and significantly (p < 0.05). This study contributes to revealing the design mechanism of thermal and moisture related properties of SFSs and developing steam protective clothing with good thermal comfort.

Ring spinning is noteworthy for its wide range of uses as well as the substantial influence of process parameters, such as spindle speed, traveler count, ring diameter, and roller pressure, on yarn quality. Despite substantial research on these parameters, the impact of spindle tape aging on yarn quality remains unexplored. This study fills a gap by investigating the effect of spindle tape lifespan on yarn-quality measures. Thirteen samples of 30 Ne were developed against different spindle tape ages such as 0 (new) to 24 months at the 2-month interval. The best spindle tape replacement interval was determined using a regression analysis using confidence and prediction bounds, as well as yarn-quality standards. The findings indicate that the strength, imperfection, and hairiness of yarn are greatly impacted by spindle tape aging. Based on the findings, it is advised that spindle tapes be replaced every 18 months to ensure good yarn quality. This study offers useful information on spindle tape maintenance to factory owners, along with doable suggestions to improve the quality of yarn production.

In this study, glass-carbon hybrid fibre reinforced polymer matrix composite is proposed to use in solar greenhouse dryer trays. The effects of hybridization on compressive instability failure are analysed by varying the glass fiber volume percentage in a composite. The study examines the compressive instability failure of the composite, considering the non-linear constitutive behaviour of the polymer matrix and initial morphological defects. Each glass and carbon fiber is modelled using 3D finite element micromechanical models. Linear buckling analysis is conducted with appropriately scaled faults. The Thermal analysis to determine heat distribution over the tray, carried out using COMSOL Multiphysics tool, solar greenhouse dryers are used to dehydrate agricultural products, preserving them for longer periods and improving their market value. The materials used in these dryer trays must meet specific performance criteria to ensure optimal drying conditions. In Greenhouse solar dryers, two commonly used tray configurations such as Stable Tray-Assisted Dryer (STAD) and Rotatable Tray-Assisted Dryer (RTAD) are considered in this study and the glass-carbon hybrid composite used in solar greenhouse dryer trays Introduced as Hybrid composite Rotatable Tray-Assisted Dryer (HRTAD), offers significant contributions by ensuring uniform and effective moisture removal and their excellent strength-to-weight ratio, corrosion resistance, heat resistance, sustainability, and long life. These properties make them a dependable and effective solution for building solar dryer components, assuring optimal performance and contributing to the overall success of solar greenhouse systems. Hybrid glass fiber composites offer several advantages that make them particularly suitable for this application.

The lower effective thermal conductivity of goose down fibres provides an excellent thermal insulator property, which is mainly assumed due to its air-entrapping ability and thus lower diffusive thermal conductivity. Although the effective thermal conductivity of a porous medium is a combination of both diffuse and radiative thermal conductivity, using an alternate approach, the present work attempted to quantify the influence of structural parameters on radiative transmittance, which is directly related to radiative conductivity that affect the overall effective thermal conductivity. A Box–Behnken design was used to study the effect of areal density, thickness of nonwovens, and blend proportion of the goose down fibres in non-wovens on the radiative transmittance. It was found that radiative transmittance does not decrease linearly with an increase in areal density. Also, the model predicted an interaction factor among the thickness of the nonwoven and the blend proportion of the goose down fibers; with an increase in thickness, radiative transmittance showed a decreasing trend; with an increase in goose down blend proportion, radiative transmittance decreased, but the extent of reduction was different for different levels of thickness. So, it was found that the multidirectional orientation of goose down fibres along with their fine barbules are the major factors that contributed to their lower radiative transmittance properties.

Color catcher sheets, developed to prevent color runs during the washing process, have found interesting applications in (bio)analytical chemistry. Both native and modified sheets can be used as low-cost, planar optical sensors for the analysis of various dyes and as a carrier for immobilization of specific ligands. Changes of sensor color can be observed by spectrophotometry or using an image analysis. Portable devices including smartphones and corresponding applications can substantially accelerate the assays. Low-cost color catcher sheets do not require any activation and can be employed for wide variety of analytical applications. This mini-review covers recent advances in the progressive applications of color catcher sheets.

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Due to its many practical advantages and positive effects on the environment, sustainable dyeing using natural substances has drawn increased attention. Based on the sustainability of the extraction of natural dyestuff from garlic (Allium sativum), the coloration of lycra viscose fabric was investigated; the ideal dye extraction conditions were as follows: an M:L ratio of 1:3, a temperature of 80 °C, and a duration of 30 min. For viscose fabric, several dyeing processes were performed utilizing natural mordants, such as orange peel and lemon peel, as well as commonly used tannic acid, copper sulfate, and ferrous sulfate with various mordanting ratios. In the entire experiment, for the first time, only one type of mordanting procedure (pre-mordanting) was used to determine the optimal outcomes of the mordants and to provide a comparison of their performances. The results revealed that viscose fabric dyeing using a pre-mordanting method with 5% orange peel as a natural mordant exhibited improved performance and higher outcomes than the other mordants. Different measurement techniques were used to determine the CIELab outputs, and a color strength (K/S) attribute experiment was used to determine the optimal value. The results from the FTIR study verified that the colored particles interacted with the viscose fabric. In addition, the results from the SEM analysis confirmed the ability of the dye to absorb into the viscose fabric surface. The elemental mapping and EDX spectra also confirmed the presence of the dye particles on the surface of the dyed fabric. In addition, the color-fastness characteristics had satisfactory fastness ratings of 4–5 for rubbing, 4–5 for washing, and 4–5 for light performance with the metal mordants. To address the actual need for viscose fabric coloration and function in clothing manufacturing, garlic (Allium sativum) dyeing of viscose fabric is a very promising alternative option to synthetic dyestuff.

This study, which has been addressed to the treatment of natural cellulosic fibers, aimed to investigate some properties of cattail, babassu coconut husk, Barú coconut husk, Brazil Nutshell husk, soybean pod, and peanut pod fibers, with alkaline/hydrogen peroxide. The fibers before and after the treatment were characterized by determination of the cellulose and lignin content as determined by scanning electron microscopy, color parameters, FTIR, X-ray diffraction, and thermal properties. As a result, the treatment has been effective in the partial removal of amorphous non-cellulosic polysaccharides, consequently increasing the availability of crystalline cellulose. The FTIR showed a reduction of the bands referring to lignin, the XRD indicated an increase in the crystallinity index, and the SEM analysis showed that the surface of the treated fibers became less rough and more homogeneous when compared with untreated fibers and that the thermal stability of the treated fibers had increased.

The dyeing processes in the textile industry generate substantial wastewater containing various dye compounds, particularly triphenylmethane dyes, which are environmentally problematic due to their persistence and potential toxicity. This study focuses on optimizing the decolorization of three specific triphenylmethane dyes (Basic Green 4, Basic Violet 3, and Bromophenol Blue) using bacterial monoculture and consortium isolated from textile wastewater. Initially, bacterial strains (Agrobacterium radiobacter, Bacillus sp., Sphingomonas paucimobilis, and unidentified filamentous bacteria) were isolated and screened for their decolorization capabilities. The most effective strains were then selected for detailed monoculture and consortium studies. Key parameters such as pH, temperature, stirring, initial dye concentration, glucose, and yeast extract were optimized to enhance decolorization efficiency. The results showed that both monocultures and consortium had significant decolorization capabilities, with the consortia outperforming the monocultures under optimized conditions. The consortia exhibited enhanced decolorization efficiency compared to individual bacterial strains, indicating synergistic interactions among the consortium members.