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This work reports changes in the mechanical and surface properties of a plain weave cotton fabric subjected to enzyme treatment with and without mechanical agitation. It also describes the influence of the property changes on the measured hand qualities. Some of the mechanical properties and the tactile qualities of the treated fabrics differ by as much as 50% compared to the untreated fabric. One-way analysis of variance reveals that almost all the measured properties (except initial thickness, percent thickness compression, and bending rigidity) of the treated fabrics differ from those of the untreated fabric. The results also reveal that there are some unique differences in properties between the fabrics subjected to enzyme treatment with and without mechanical agitation, implying that the level of mechanical agitation during treatment can significantly alter the finishing effects, including the thermal comfort performance of the treated fabrics.

Hemp fabric is hydrolyzed with cellulase, hemicellulase/cellulase, and cellulase plus additional β-glucosidase. The effect of the admixture of hemicellulase and β-glucosi dase is evaluated in terms of hydrolysis rate and product properties. The influence of mechanical action during the treatment is also taken into account. Treated samples are characterized by weight loss per incubation time, tensile strength, crystallinity, acces sibility, and pore structure. The admixture of hemicellulase and,β-glucosidase produces only minor effects without mechanical action on the hydrolysis rate, but mechanical action applied during the treatment dramatically increases weight loss. While crystal linity changes upon hydrolysis are insignificant, the pore structure is strongly influenced by the choice of enzyme system. Hemicellulase seems to promote the formation of smaller pores, while cellobiase forms larger pores.

Three different scouring methods are applied to open-end and ring spun yarns prior to hydrogen peroxide bleaching with and without metal ions present. The scouring procedures include a penetrating treatment with aqueous sodium hydroxide solution, a nonswelling solvent extraction, and a fiber surface-affecting treatment with pectinase enzymes. Properties of the treated yarns and fiber damage are studied after each process step. Conventional scouring with sodium hydroxide followed by peroxide bleaching causes the highest deterioration on the molecular level, but results in a high level of whiteness, Solvent extracted yams exhibit superior tensile strength, which is preserved more or less unchanged throughout any subsequent treatment. The bioscouring process with enzymes renders the yams strikingly soft. The effects are generally more pro nounced for open-end spun yams, suggesting that differences in yarn structure may have an impact on the effectiveness of scouring.

Relations were studied between fiber structure and mechanical properties of cotton fibers crosslinked with 1,2,3,4 butanetetracarboxylic acid (BTCA). BTCA was either applied directly to the fibers (NPT) or after they had received a swelling treatment with caustic soda (MER), liquid ammonia (LAT), or monomethylamine (MMA). In some instances BTCA was applied before the caustic treated fibers had been dried (NDMER). The water retention value (WRV) of MER fibers was markedly higher than that of NPT, LAT, or MMA fibers. After BTCA treatment, however, the WRV of MER fibers fell sharply, but that of MMA or LAT samples did not. Thus the WRV s of BTCA MER and NDMER fibers approached those of MMA and LAT products. The breaking force of BTCA fibers approached the same value at high BTCA contents, with or without mercerization or methylamine preswelling. It appeared that LAT cotton might retain greater strength than the other samples at high BTCA contents. The breaking extensions of BTCA fibers that had received a preswelling treatment were higher than those of fibers that had not been pretreated. Properties of MER and NDMER BTCA fibers were similar, even though it appeared that the BTCA was more uniformly distributed in the NDMER fibers. The breaking twist angle ( BTA ) was determined as a measure of brit tleness ; the BTA relation with extension for the BTCA samples was similar to a previously determined relation for cotton treated with dimethyloldihydroxyethyleneurea.

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 yam 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 << 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 accessiblc 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 yams within the samples.

Cotton fabric is subjected to enzymatic hydrolysis with cellulases before and after dyeing. The effects of direct dyes of increasing molecular size on the rate of the en zymatic hydrolysis reaction are investigated, along with mono- and bifunctional reac tive dyes with different functional groups. All reactive dyes studied and especially bifunctional reactive dyes, have a decelerating influence on enzymatic attack. The effect of the direct dyes depends strongly on the enzymatic treatment duration. Moisture regain values of enzyme treated fabric suggest a transient state of somewhat increased disorder of the cellulose structure at a specific stage of hydrolysis, which is alleviated by longer incubation times. At this stage, direct dyed fabric shows a hydrolysis rate approximately equal to or slightly higher than undyed fabric.