Study On Technology And Mechanism Of Viscose Fibers Surface Modification

With the improvement of people's living, functional and eco-friendly textile materials are need by more and more people. As is well known, the surface properties of textile materials are more important than their bulk properties, a number of attempts of surface grafting-modification of fibers have been made to change their surface chemical composition and structure to improve their property. As a class of natural cellulose fibers, viscose fibers have been widely used as textile materials because of its good softness, perfect moisture absorption and the affinity for body. In this paper, the surface modification technologies were investigated to improve the strength of viscose fibers and prepare functional viscose fibers. After viscose fibers were modified, a functional layer was formed on the surface of viscoae fibers, the wet strength of fibers was improved and the antibacterial viscose fibers and keratin viscose fibers were produced successfully. At the meantime, the mechanism of modification was studied by analyzing their structure and properies.Cellulose fibers were chemically modified on surface by KMnO₄ premodification and acrylamide polymerization. The grafted viscose fibers had good wet strength, 1.25cN/dtex, 4.2% higher than parent fibers. To further improve the wet strength, glutaraldehyde was used for the formation net structure in the crosslinking reaction process with polyacrylamide. The crossliked viscose fibers had improved wet strength, with the maxinum value being 1.41cN/dtex, 17.5% higher than parent fibers. After viscose fibers were pre-treated by KMnO₄, KMnO₄ was absorbed onto surface of fibers, resulting in the formation of surface radicals and the subsequent, which initiatiion of the grafting polymerization of acrylamide. On the other hand, acrylamide was also grafted onto the surface of viscose fibers by reaction with aldehyde and carboxyl group formed by KMnO₄ oxidation the surface of fibers. The modified viscose fibers had different surface morphology, chemical structure, microstructure and thermal property from parent fibers, and the wet strength were increased.The inorganic antibacterial agent ( particle size 60nm) was prepared by adsorption using nano-SiO₂ as carrier and silver nitrate as Ag source. The silver-loading nano-SiO₂ antibacterial agent was surface-modified using KH-550 as modifier and glycol as solvent. After modification, the agglomeration of antibacterial agent was effectively pervented and the lipophilic property was improved. The study clearly demonstrated that modified antibacterial agent had excellent broad-spectrum antibiosis property, giving the antibacterial ratio up to above 90% against E. coli and S. aureus. The modified antibacterial agent was used to prepare antibacterial viscose fibers. The antibacterial layer was formed by covalent bonding between antibacterial agent and viscose fibers through acrylamide as coupling laryer. The antibacterial viscose fibers showed excellent antibacterial performance and wash-resistant property. In other words, the antibacterial rate was higher than 80% after 30 times of repeated wash.The solutions of wool keratin with different molecular weight were prepared by reduction method. The results of fourier transform infrared(FT-IR) indicate that the molecular structure of keratin had little change, the integrality of the keratin macro-molecules was kept unchanged, but the S-S bond and -OH bond were broken. Structural studies carried out by X-ray diffraction (XRD) suggest that the arrangement of keratin molecules was destroyed, thus showing mainly amorphous structure.The keratin viscose fibers were prepared through surface grafing method. The morphology, surface structure and mechanical properties of keratin viscosefibers were affected by treatment temperature, time and concentration of keratin solution. The optical treatment parameters for viscose fibers by keratin solution were investigated. The surface of viscose fibers was covered with keratin, and the wet strength was improved. At the same time, the thermo-stability of treated viscose fibers was decreased.