Structural Changes in Cotton: Effect of Premercerization Conditions on Subsequent Cross-Linking

Abstract

Structural changes due to tension applied to caustic-swollen yarns were studied. It was found that the cross-linking of yarns which had been mercerized slack, at normal length, or slack and then restretched to normal length produced differences in tenacity and X-ray orientation. It was concluded that this was due to structural rearrangements induced by the application of load to fiber systems. Differences in wet pickup of the cross-linking resin were shown to produce differences in the fiber fragmentation pattern but not in the layer-expansion pattern. Only a fraction of the added cross-linking resin was considered to have contributed to the properties usually attributed to cross-linked yarns. The regions believed responsible for the effect of cross-linking are the less ordered lattices close to the crystalline structures. The strength retained after cross-linking was dependent on the tension and the method of its application. Differences in the degree of conversion of cellulose I to cellulose II were noted in the slack-mercerized yarns treated with different alkali metal hydroxides. These differences, with the exception of lithium hydroxide, correlated with swelling effectiveness of the alkalis used.