Effects of Mercerization, Submercerization, and Liquid Ammonia on Fiber Morphology of Neps in Cotton Fabric

Abstract

Cotton print cloth containing both immature fiber neps and process neps composed of torn and ruptured mature fibers was treated with mercerizing and submercerizing strength sodium hydroxide and with liquid ammonia. Scanning electron microscopic examination of mercerized samples showed separation of the nep mass and swelling of individual fibers in both types of neps. Treatment with submercerization strength sodium hydroxide resulted in swelling of surface fibers of the nep but retention of much of the overall fiber compactness. Liquid ammonia appeared to have little effect on the swelling of the individual immature fibers, but did achieve a separation of the compact nep mass. After dyeing with each of ten direct dyes, the mercerized samples showed an average increase in visible coverage of neps of 95%, while the dyed sub- mercerized samples showed an average increase in nep coverage of 86%. After liquid ammonia treatment, significant improvement in nep coverage occurred with five of the ten dyes examined.