Effects of sodium hydroxide and liquid ammonia treatments on shape changes of cross-sectional of cotton fibers due to swelling

摘要

The cotton fabrics treated with formaldehyde vapor show high wash and wear (W&W) properties, but poor tensile strength as compared with the resin treated fabrics. This property is expected to be improved by liquid ammonia pre4reatment before thetreatment with formaldehyde vapor. In this study, from a practical viewpoint of formaldehyde vapor treatment of cotton fabrics, the microscopic and macroscopic strain relaxation along the cross sectional direction of cellulose fibers by the pre-treatmentwith liquid ammonia, sodium hydroxide and sodium hydroxide/liquid ammonia were examined in terms of crystallinity, crystalline transition (microscopic uniformity index), barium activity number(amorphous content index) and aspect ratio of cross section ofa fiber(macroscopic index). It was found that all examined pre-treatmants bring about considerable changes in fine structural properties, but the liquid ammonia pre-treatment is superior to the other pre-treatments. This is due to the fact that the liquid ammonia pre-treatment brings about a uniform strain relaxation of cellulose fibers.