Study On The Application Of Enzyme In The Pretreatment Of Cotton Fabrics

The traditional pretreatment is carried out with caustic soda at high temperature, which not only wastes energy and water, causes pollution, but also damage fabrics. It's urgent to develop a novel, gentle and environmental-friendly pretreatment method. Researchers pay more attention to bio-pretreatment by its advantages of dedicated, gentle and environment-protective. Compared to traditional pretreatment, some performance pretreated by enzyme should be improved, such as whiteness, absorbency and removal of seed-coat fragments. The relating properties of amylase, pectinase, and mixed-enzyme (amylase, pectinase, cellulase, xylanase and lipase) were investigated systematically, which provides a theoretical support for developing enzymatic pretreatment for cotton fabrics.The structure and chemistry composition of cotton, the principles of enzymes, and the factors of the enzyme activation were dicussed. The present situation and development of enzymes were also studied. Based upon this, the properties of amylase and pectinase used for enzymatic pretreatment was studied, such as the optimum enzyme reaction condition, the stability of enzyme activity, the activity and stability in mixed-enzyme (amylase, pectinase, cellulase, xylanase and lipase), the stability in technological conditions, the effects of textile auxiliaries, buffers and aqueous phase conditions, the storage stability, etc.As the properties of enzymes were researched above, pH, enzyme concentration, temperature and treatment time in desizing process were investigated.The desizing technic with amylase was then obtained through determining desizing rate by perchloric acid method. For comparison, a sample of cotton fabric was desized conventionally in boiling alkaline solution. The content of pectin on cotton fabrics remaining after pretreatment was analyzed by ruthenium red staining method and carbazole spectrophotometric method. The residual cotton wax content was also analyzed by oil red staining method and ether solvent extraction method. The effect of mixed-enzyme (amylase and pectinase) concentration on the efficiency of pretreatment was evaluated by monitoring the treated cotton fabrics for residual starch and pectin content, whiteness, tearing strength and so on. The cotton fabrics with PVA/starch size was treated by one-bath process of desizing and scouring with mixed enzymes at low temperature, then bleached with conventional method, and the properties of the treated cotton fabrics was tested. Treated cotton fabrics can meet the semi-finished product's quality, such as whiteness, wettability, the removal of seed-coat fragments and so on.