Search Results (3)

Silver nanoparticles (AgNPs) have attracted considerable interest for various applications, including antiviral and antimicrobial treatments, textile nanocomposites, heat transfer and strain sensing textiles, flexible electronics, and smart textiles. Their unique properties, determined by their size, shape, and morphology, render them suitable for a wide range of uses, such as antimicrobial treatments, anticancer therapy, drug delivery, personal protective equipment (PPE), and catalysis. In this investigation, we present an in situ reactive technique for the self-assembly of AgNPs directly onto cotton yarn. A systematic investigation was undertaken to establish the influence of several synthesis parameters on the average size of AgNPs. The variables under consideration included the ambient vacuum conditions, the concentration of both Ag precursor and reducing agent, the growth temperature, and the duration of thermal treatment. By precisely optimizing these parameters, we successfully regulated the AgNPs size range between 10 and 50 nm on the cotton yarn. The findings of this study elucidate the methodology of the controlled synthesis of AgNPs on cotton yarn for potential advancements in smart textile technologies. Full article

Poly(glycolic acid) (PGA) is a rapidly degradable polymer mainly used in medical applications, attributed to its relatively high cost. Reducing its price will boost its utilization in a wider range of application fields, such as gas barriers and shale gas extraction. This article presents a strategy that utilizes recycled PGA as a raw material alongside typical carbon nanomaterials, such as graphene oxide nanosheets (GO) and carbon nanotubes (CNTs), to produce low-cost, fully degradable yarns via electrospinning and twisting techniques. The results demonstrate that the tensile strength of the PGA/GO composite yarn increased to 21.36 MPa, and the elastic modulus attained a value of 259.51 MPa with a 3 wt% of GO loading. The addition of an appropriate amount of GO enhances the tensile resistance of the composite yarns to a certain extent. However, excessive application of GO and CNTs can lead to surface defects in the nanofibers, reducing their mechanical properties. Moreover, the integration of both materials could inhibit the degradation process of PGA to some extent, thereby partially addressing the issue of excessive degradation rates associated with the relatively low molecular weight of recycled PGA. Full article

Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the growing of CHI crystals. Moreover, the preferential orientation of both CNFs and CHI crystals along the spun fiber direction was revealed in the two-dimensional X-ray diffraction patterns. By increasing the CNF amount up to the optimum concentration of 0.4 wt % in the viscous CHI/CNF collodion, Young’s modulus of the spun fibers significantly increased up to 8 GPa. Similarly, the stress at break and the yield stress drastically increased from 115 to 163 MPa, and from 67 to 119 MPa, respectively, by adding only 0.4 wt % of CNFs into a collodion solution containing 4 wt % of chitosan. The toughness of the CHI-based fibers thereby increased from 5 to 9 MJ.m⁻³. For higher CNFs contents like 0.5 wt %, the high mechanical performance of the CHI/CNF composite fibers was still observed, but with a slight worsening of the mechanical parameters, which may be related to a minor disruption of the CHI matrix hydrogel network constituting the collodion and gel fiber, as precursor state for the dry fiber formation. Finally, the rheological behavior observed for the different CHI/CNF viscous collodions and the obtained structural, thermal and mechanical properties results revealed an optimum matrix/filler compatibility and interface when adding 0.4 wt % of nanofibrillated cellulose (CNF) into 4 wt % CHI formulations, yielding functional bionanocomposite fibers of outstanding mechanical properties. Full article