Structural changes in Tencel by enzymatic hydrolysis

The NaOH-, fabrillation-, and cellulase- treated Tencel fabrics were charac terized by weight loss, tensile strength, scanning electron microscopy (SEM ) analysis, X-ray diffraction analysis, measurements of moisture regain and dye adsorption (K/S value), degree of polymerization (DP), and copper numb er. Weight loss increased and tensile strength decreased with increase in c ellulase concentration and treatment time. At a similar weight loss, tensil e strength retentions of the NaOH-pretreated samples were better than those of the NaOH-nontreated samples because of more uniform enzymatic hydrolysi s. SEM photographs showed more surface peeling and interfibrillar splitting as enzymatic hydrolysis progressed. Crystalline structure and degree of cr ystallinity were not much changed by cellulase treatment. As enzymatic hydr olysis progressed, moisture regain and WS value increased slightly due to i ncrease of specific surface area by fibrils. DP initially decreased as enzy matic hydrolysis progressed and then leveled off. Copper number increased l argely at an initial stage of degradation and then decreased gradually, The NaOH-pretreated samples showed higher degree of crystallinity, DP, moistur e regain, and WS value, but lower copper number than the NaOH-nontreated on es. These results were attributed to extraction of short chain molecules in the amorphous region during NaOH pretreatment and change of amorphous regi on into the open-up structure. (C) 2000 John Wiley & Sons, Inc.