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The selective hybrid formation of numerous tiny carbon nanofibers (CNFs) in carbon-based nonwoven fabrics (c-NFs), namely CNFs formed only on the surfaces of individual carbon fibers (i-CFs) constituting c-NFs and not on the surfaces of carbon microcoils (CMCs), could be formed by the incorporation of H2 gas flow into the C2H2 + SF6 gas flow in a thermal chemical vapor deposition system. On the other hand, the nonselective hybrid formation of numerous tiny CNFs in c-NFs, that is, tiny CNFs formed on the surfaces of both i-CFs and CMCs, could be achieved by simply modulating the SF6 gas flow on and off in continuous cycles during the reaction. Detailed mechanisms are suggested for the selective or nonselective formation of tiny CNFs in c-NFs. Furthermore, the electromagnetic wave shielding effectiveness (SE) values of the samples were investigated across operating frequencies in the 8.0–12.0 GHz range. Compared with previously reported total SE values, the presently measured values rank in the top tier. Although hybrid formation reduced the electrical conductivity of the native c-NFs, the total SE values of the native c-NFs greatly increased following hybrid formation. This dramatic improvement in the total SE values is ascribed to the increased thickness of c-NFs after hybrid formation and the electromagnetic wave absorption enhancement caused by the intrinsic characteristics of CMCs and the numerous intersections of tiny CNFs.

Polymer fabrics are versatile materials used in various fields. Surface modification methods for hydrophobic polymer fibers have been developed to endow the materials with water wettability and functionality. Nevertheless, it remains a challenge to freely introduce functional groups to polymer fiber surfaces in a simple manner. Herein, we report the decoration of nonwoven fabric surfaces with azidated cello-oligosaccharide assemblies via molecular self-assembly. Cello-oligosaccharides with a terminal azido group were enzymatically synthesized and allowed to self-assemble in polyolefin, polyester, and vinylon nonwoven fabrics. It was found that the functional oligosaccharides formed bark-like assemblies on the nonwoven fiber surfaces, probably through heterogeneous nucleation. The hydrophilic oligosaccharide assemblies made the hydrophobic nonwoven surfaces water-wettable. Moreover, the azido group at oligosaccharide terminal was available for the post-functionalization of the modified nonwovens. In fact, an antigen was successfully conjugated to the modified nonwovens via the click chemistry. The antigen-conjugated nonwovens were useful for the specific and quantitative detection of a corresponding antibody. Our findings demonstrate the great potential of cello-oligosaccharide assembly for the functionalization of fabrics and other polymeric materials., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)

ITA, the Italian Trade Agency and ACIMIT, the Italian textile machinery manufacturers association organized a two-day marathon webinar on June 17-18 primarily focusing on the technology relevant to Pakistan's textile [...]

Unsaturated fluid flow in thin porous media depends on hydraulic properties, such as the capillary pressure, P c , as a function of saturation, S. We measured this relationship for two different types of compressible thin hydrophilic fibrous layers under varying conditions. Among other factors, we changed the number of layers and the overburden pressure (i.e. the confined solid pressure applied on top of the sample) imposed on one layer or a stack of layers. Applying an overburden pressure drastically affected the P c (S) curves. However, increasing the number of fibrous layers had little impact on the capillary pressure–saturation curves. We also investigated the effect of multiple imbibition–drainage cycles on the P c (S) data. Measured data points were used to find general expressions for the P c (S) relationships of compressible thin porous media. Existing quasi-empirical correlations used in vadose zone hydrology, notably expressions by van Genuchten (Van Genuchten MTh. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 1980; 44: 892-898) and Durner (Durner W. Hydraulic conductivity estimation for soils with heterogeneous pore structure. Water Resour Res 1994; 32: 211–223) for single- and dual-porosity media, respectively, were employed to fit the measured data points. [ABSTRACT FROM AUTHOR]

Compression and strength properties of viscose/polypropylene nonwoven fabrics has been studied. Compression behavior of the nonwoven samples (sample compressibility, sample thickness loss & sample compressive resilience) have been analyzed considering the magnitude of applied pressure, fabric weight, fabric thickness, and the porosity of the samples. Based on the calculated porosity of the samples, pore compression behavior (pore compressibility, porosity loss & pore compressive resilience) are determined. Equations for the determination of pore compressibility, porosity loss, and pore compressive resilience, are established. Tensile strength and elongation as well as bursting strength and ball traverse elongation are also determined. The results show that the sample compression behavior as well as pore compression behavior depend on the magnitude of applied pressure. At the high level of applied pressure, a sample with higher compressibility has the lower sample compressive resilience. Differences in pore compressibility and porosity loss between investigated samples have also been registered, except in pore compressive resilience. Sample with the higher fabric weight, higher thickness, and lower porosity shows the lower sample compressibility, pore compressibility, sample thickness loss, porosity loss, and tensile elongation, but the higher tensile strength, bursting strength, and ball traverse elongation. [ABSTRACT FROM AUTHOR]

Ethnic value of many known plants are underexploited for medicinal application besides their proven traditional qualities. One such plant known for wound healing is Tridax procumbens. This plant has wound healing property and is commercially unexploited. Silver nanoparticle (Ag‐NP) were synthesized using this plant extracts using different solvents (methanol, ethyl acetate and aqueous), which exhibit resonance at 426, 424 and 418 nm, respectively. This plant‐mediated Ag‐NPs have strong anti‐bactericidal activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenes, Klebsiella pneumonia, Serratia marcescens and Bacillus subtilis with methanol extract. Further instance, elemental composition was confirmed by energy dispersive X‐ray analysis and particle size ranges were observed at 80–200 nm with spherical shape nanoparticles by scanning electron microscopy and transmission electron microscopy analysis. The biocompatibility of Ag‐NPs was assessed using fibroblast cell line (L929) by MTT assay with 109.35 µg IC50 value. The oxygen plasma treated and non‐treated bamboo spunlaced nonwoven fabrics were coated with the Ag‐NPs by exhaust method. Contact angle and water retention revealed significant difference in absorption ability of plasma treated fabric. Field emission scanning electron microscopy revealed the presence of Ag‐NPs in plasma coated fabrics. The fabricated cloth was studied for anti‐microbial and microbial penetration ability. [ABSTRACT FROM AUTHOR]

Lightweight and flexibility nickel-metallized polyimide nonwoven fabric for EMI shielding is fabricated by polydopamine roughening, palladium-free activation, electroless plating, and octadecanethiol corrosion-resistant treatment. The strong roughening effectively enhances the bonding force between nickel plating and polyimide fibers, thereby improving the high/low-temperature resistance and durability of composite. Meanwhile, the self-assemble modification of octadecanethiol on their surfaces effectively achieves the inhibition of Ni plating corrosion. More importantly, the corresponding metallization endows it with an excellent Joule heating in cold EMI Shielding environment. [Display omitted] • A novel Ni-metallized EMI shielding fabric is fabricated by electroless plating. • Polydopamine roughening enhances the bonding force between Ni-plating and fibers. • The strong binding force improves temperature resistance and durability of composite. • The modification of octadecanethiol achieves the inhibition of Ni plating corrosion. • Surface metallization endows it with an excellent Joule heating in cold weather. Designing and fabricating efficient electromagnetic interference shielding materials has become a significant and urgent concern. Hence, a novel lightweight and flexible metallized polyimide nonwoven fabric is successfully prepared by polydopamine roughening, palladium-free activation of chloroplatinic acid, electroless nickel plating, and octadecanethiol corrosion-resistant treatment. As a result, the efficient construction of metallized surface on polyimide fibers facilitates the formation of multiple scattering for incident electromagnetic waves, leading to an excellent electromagnetic interference performance. More importantly, the strong binding force between nickel plating and polyimide fiber substantially improves the high/low-temperature resistance, endowing the composite with excellent stability and durability in electromagnetic interference performance. Meanwhile, the self-assembly modification of octadecanethiol on the surfaces of nickel plating effectively achieves the inhibition of metal corrosion. Additionally, the high electrical conductivity of metallized polyimide nonwoven fabric endows it with a rapid-responsiveness Joule heating performance, which makes it promising to become an efficient electromagnetic interference shielding material with a distinct competitive advantage in the cold environment. [ABSTRACT FROM AUTHOR]

Filtration systems used in technical and medical applications require components for fine particle deep filtration to be highly efficient and at the same time air permeable. In high efficiency filters, nonwoven meshes, which show increased performance based on small fiber diameters (e.g., using nanofibers), can be used as fine particle filter layers. Nanofiber nonwoven meshes made by electrospinning of spider silk proteins have been recently shown to exhibit required filter properties. Needle-based electrospinning, however, is limited regarding its productivity and scalability. Centrifugal electrospinning, in contrast, has been shown to allow manufacturing of ultrathin polymer nonwoven meshes in an efficient and scalable manner. Here, continuous roll-to-roll production of nonwoven meshes made of recombinant spider silk proteins is established using centrifugal electrospinning. The produced spider silk nanofiber meshes show high filter efficiency in the case of fine particulate matter below 2.5 µm (PM2.5) and a low pressure drop, resulting in excellent filter quality.

The tensile testing of a needle-punched nonwoven fabric is presented. A high-sensitivity Split-Hopkinson Tensile Bar device was specifically designed for this purpose. The strain gauge measurements were combined with high-speed photography and Digital Image Correlation to analyse the deformation micromechanisms at high strain rates. The experimental set-up allowed to determine the wave propagation velocity of the as-received nonwove fabric, the evolution of the strain field with deformation and the wave interaction inside the fabric. The deformation was accommodated by the same micromechanisms observed during quasi-static tensile testing and ballistic impact, which comprised fibre straightening, rotation and sliding. Heterogeneous strain fields were developed in the nonwoven fabric as a result of the non-linear pseudoplastic response of the fabric and the internal dissipation due to the frictional deformation micromechanisms, preventing the propagation of high magnitude strain waves into the specimen. Additionally, the output forces were analysed to determine the influence of high-strain rates in the mechanical response of the nonwoven fabric, finding an increment of the stiffness for low applied strains under dynamic loading. These findings provide the basis to develop strain-rate dependent constitutive models to predict wave propagation in needle-punched nonwoven fabrics when subjected to impact loads.