Enzymatic Application In The Surface Modification Of Polyacrylic Fibers

Enzyme has very particular and efficient character of catalysis and will not lead to pollution, so its application in textile process has a broad future. As to the modification means of polyacrylic fibers , the thesis has contrasted the enzymatic means with the traditional ones, and made a research about the application of enzyme in the surface modification of polyacrylic fibers. The main modification principle is that the nitrile groups on the surface of acrylic fibers could be selectively hydrolyzed to the corresponding amidic groups by nitrile hydratase from Arthrobacter sp. Ecu1101.The thesis has optimized the process parameters of enzymatic modification at first. The main process parameters are as follows: surfactants, temperature, pH, time, rotate speed of flasks , enzymatic concentrations. After modification the hydrophilicities and the anti-static properties of the fibers have also been improved.In order to strength the contact of enzyme with fibers , the thesis has taken the pretreatment by means of alkali and organic solvents.Alkali pretreatment can make a little amount of nitrile groups of acrylic fibers hydrolyze and form carboxyl groups in the alkali condition ,which can weaken the force between the molecules on the surface of acrylic fibers and enhance the rule of enzyme to some extent .But the means will change the fibers into yellow color and make the handle worse .In addition ,the alkali hydrolyzation extent is difficult to control, which maybe lead to destroy some excellent physical features of arylic fibers.Pretreatment of some kinds of organic solvents could help the acrylic fibers to be more accessible to nitrile hydratase and enhance enzymatic-modification. From experimentation, we can conclude that benzyl alcohol is the best solvent to promote the enzymatic modification .Then the thesis has optimized the pretreatment conditions too. In the end, the fibers was treated in the optimized conditions of pretreatment and enzymatic modification. The modified acrylic fibers became more hydrophilic and anti-static, which were shown by the change of humidity regain, water contact angle and half-decay times. Besides those, the amide groups formed during enzymatic modification enabled the acrylic fibers to be dyed with acid dyes.