Liquid Ammonia and Caustic Mercerization of Cotton Fibers Using X-Ray, Infrared, and Sorption Measurements

X-ray and infrared spectroscopic analyses were used to measure crystallinity of cotton fibers swollen in liquid ammonia and an aqueous solution of caustic soda. Changes due to such swelling, which took place in the accessible regions, were determined by moisture regain and iodine and dye sorption. Results showed that mercerization treatments lead to a sharp decrease in cellulose crystallinity as assessed by determining the increase of reactivity of cellulose towards dye sorption. Iodine and moisture sorption were used to estimate cellulose accessibility. From these measurements general correlations were obtained between the x-ray crystallinity index and iodine sorption values, as well as a correlation between crystallinity ratio determined by infrared spectroscopy and accessibility determined by moisture sorption.