Quality Assessment of Socks Produced from Viscose and Lyocell Fibers

Most casual socks are produced from cotton and are usually combined with synthetic fibers. The suitability of viscose and lyocell fibers for knitting socks needs to be investigated further. Therefore, three series of plain socks were produced, composed in the largest content from single-spun viscose or lyocell yarns fully plated with texturized polyamide 6.6 multifilament yarn. The quality of three types of main yarns manufactured by ring, open-end rotor, and air-jet spinning processes and two types of polyamide plating yarns used in the production of socks were assessed together with the structural, usage, and comfort quality of the socks before and after simulating household laundering. In comparison with cotton socks produced from ring-spun yarns under the same conditions, the results showed that viscose and lyocell socks have better moisture absorption and breathability, comparable dimensional stability, and lower abrasion resistance; lyocell socks have lower thermal resistance; and viscose socks are less prone to surface pilling after wet pretreatment.

Optimisation of AgNP Synthesis in the Production and Modification of Antibacterial Cellulose Fibres

The main aim of the presented research is to determine the optimal conditions for the production of silver nanoparticles (AgNPs) in N-methylmorpholine-N-oxide (NMMO), which will potentially allow to obtain small nanoparticles with uniform diameter distribution. In this paper, NMMO is used in the fibre production process, both as a direct cellulose solvent and as an Ag+ reducing system. From an industrial point of view, this method is very promising because it allows to reduce the amount of used chemicals. The UV/Vis, DLS and TEM analysis proved that the synthesis temperature and time could play a key role in nanoparticle growth control in NMMO. It was found that the optimal conditions for AgNPs synthesis are 100 °C and 0.33 h. The estimations of the antibacterial activity of the fibres were completed. The applied AgNPs synthesis conditions allow to obtain antibacterial fibres with a wide range of applications, mainly in medicine.

Preparation and Characterization of Carbon Fibers from Lyocell Precursors Grafted with Polyacrylamide via Electron-Beam Irradiation

Carbon fibers, which act as reinforcements in many applications, are often obtained from polyacrylonitrile (PAN). However, their production is expensive and results in waste problems. Therefore, we focused on producing carbon fibers from lyocell, a cellulose-based material, and analyzed the effects of the process parameters on their mechanical properties and carbon yields. Lyocell was initially grafted with polyacrylamide (PAM) via electron-beam irradiation (EBI) and was subsequently stabilized and carbonized. Thermal analysis showed that PAM grafting increased the carbon yields to 20% at 1000 °C when compared to that of raw lyocell, which degraded completely at about 600 °C. Stabilization further increased this yield to 55%. The morphology of the produced carbon fibers was highly dependent on PAM concentration, with fibers obtained at concentrations ≤0.5 wt.% exhibiting clear, rigid, and round cross-sections with smooth surfaces, whereas fibers obtained from 2 and 4 wt.% showed peeling surfaces and attachment between individual fibers due to high viscosity of PAM. These features affected the mechanical properties of the fibers. In this study, carbon fibers of the highest tensile strength (1.39 GPa) were produced with 0.5 wt.% PAM, thereby establishing the feasibility of using EBI-induced PAM grafting on lyocell fabrics to produce high-performance carbon fibers with good yields.