ENZYMATIC-HYDROLYSIS OF COTTON, LINEN, RAMIE, AND VISCOSE RAYON FABRICS

Cotton, linen, ramie, and viscose rayon fabrics along with a cotton/linen blend were hydrolyzed with cellulase from Trichoderma viride. Surface fibrils were eliminated by a 6 hour treatment in all cases. The loss of fibrillar matter appeared to be the primary cause of weight loss at this stage. On prolonged treatment, cotton, linen, and viscose rayon lost weight at a faster rate than ramie and the cotton/linen blend. The fall in yarn strength was progressive with increasing weight loss for cotton and viscose, while for linen and ramie it was slight initially and then increased sharply. Retention of strength after 48 hours' incubation time increased in the order viscose rayon much less than cotton < ramie < linen, whereas weight loss increased in the order ramie < linen < cotton < viscose rayon. X-ray crystallinity and moisture sorption of the samples did not change after the treatment, indicating that the mechanism of endwise attack of the cellulase at accessible cellulose chains on crystallite surfaces appeared to apply to all four fibers. The location of enzymatic attack could be monitored with a light microscope using Congo red staining in the case of cotton and linen, but not ramie or rayon. Changes in surface morphology could be followed for all the enzyme-treated fibers by scanning electron microscopy. Additionally, mechanical tests demonstrated the changes in stretchability and stiffness of the fabrics and the mobility of yarns within the samples.