| The cotton pre-treatment process with enzymes, which had mild treatment conditon, energy-saving and environment-friendly consumption, was widely recognized as the ideal replacement process of the alkaline scouring process to the cotton. The enzymatic properties of xylanase were studied in this dissertation with the effect of pH, temperature, different surface active agent and metal ion on the xylanase And the effection of xylanase on the degradation of the cotton fabric was explored in different temperature after dynamic equation of the xylanase was fitted. The effection of the mass of enzymes, pH, temperature were analysed on the degradation of the cotton seed hull fragments with the application of both xylanase and cellulase.Base on previous studies, the cotton fabric pre-treatment process with 5 different enzymes was discussed in detail. By testing weigh loss, whiteness, wettability, the removal of cotton seed hull fragments, tensile after treatment, the factor which could affect the process was analysed. The main contents of thi s di ssertati on are as follows:(1) The results showed that, as dilution times and the mass of substrate increased; xylanase activity increased. But they could not infinitely increase because it would lead to measurement error. The enzymatic properties of xylanase was studied:the optimum react time was 20min, the optimum pH was 6.0 and optimum temperature 60℃. The xylanase had a good stability Under pH=6 the phosphate buffer system in 4h, with over 85% of the xylanase activity maintained; but, Activity decreased significantly when xylanase was placed pH=8 (Na2CO3 plus water) system, In 3-6 hours, the relative activity was below 50%. There is only a marginal difference between the absorbency of reference solutions with different buffer solutions and reaction temperature. Therefore, to reduce the procedure, we can use one reference solution with one buffer solution and reaction temperature. In addition, the influence on xylanase was distinguished with different chemical agents. (2) The best descri pti on of the degradati on of cotton seed coat by xylanase was achi eved asα/(1-α)=(K·t)χ.Based on that, the rate (v) of the degradation of cotton seed coat can be calculated for different temperature. The results indicated that the rate (v) was greatly higher at 60℃than any other temperature. The addition of the chemical agents had little effect on the treatment with xylanase.(3) If we only use xylanase to degrade the cotton seed hull fragments in cotton fiber, it would take longer ti me as well as an incompl ete scouring progress. Cotton fibric was subjected to bio-treatment with both xylanase and cellulase to degrade the cotton seed hull fragments. This article focused on the result of the bio-treatment with xylanase combined with cellulose. Influence of temperature, pH and concentration on degradation of the cotton seed hull fragments was analyzed.(4) The washing conditions in one bath enzyme desi zing and scouring process was washing with hot water(95℃×5min)→washing with hot water (75℃×5min)→rinsing in cold water. There had little effection on the enzymatic treatment with hot water pre-treatment. Using padding one-bath enzyme desi zing and scouring in the fabric pretreatment, there is a certain improvement of wettability. Afer the cotton fabric with dipping oxygen bleaching, the wettability, the whiteness and the removal of the cotton seed hull fragments had greatly i mproved. The chemical agent based on scouring agent 88,28A, JFC and sodium silicate work well in the pad steaming process. At last, there was an acceptable fabric strength retention after pretreatment by bio-desizing and bio-scouring and bleaching, which could meet the requirements of follow process.
|
PDF Full Text Request