Temporary tensile strength for cotton yarn via polymeric coating and crosslinking

Abstract

In the textile industry, the coating or sizing of cotton yarn aims to increase its tensile strength during weaving processes. The choice of sizing formulation is strategic to provide maximum process performance. Therefore, the objective of this investigation is to study the coating of cotton yarn using poly(vinyl alcohol), aiming to provide temporary tensile strength to it. To increase the tensile strength of the coating layer, crosslinking processes, such as via UV-C radiation and glutaraldehyde were studied. The influence of the coating process on the resistance of the yarn was measured by tensile tests. Different operational conditions were tested, such as molecular weight and polymer concentration, drying temperature of the yarns, crosslinking time, and glutaraldehyde concentration. Characterization analyzes, such as DSC, and SEM were carried out to better understand the results, which were all processed statistically. According to the results, the crosslinking of the yarns with glutaraldehyde caused a considerable reduction in polymer crystallinity, affecting the performance and stability of the yarn, impairing its mechanical properties. However, coating with PVA and crosslinking via UV-C radiation, increased the tensile strength of the yarn by up to 56% when compared to raw yarn, due to the creation of a new crystalline network reinforced by the bonds of crosslinking. The application of UV-C radiation proved to be promising since it eliminates the use of chemical reagents, avoiding the generation of toxic waste at the end of the process.