Study On Improving Water-Solubility Of Chitin Size By Enzyme

Sizing agents not only relate to the quality and efficiency of production,but also affect the environment-protecting of consumption and finishing.There are two ways for sizing agents polluting environment:first,left sizing agents during modulating and untreated wasted water could make damage to our environment;second,the indisposed water during sizing process after weaving. In additional,some sizing substance what is left on fabric after desizing is also not health for human beings.For weaving enterprises,it is meaningful that adopting green, environment-protecting sizing agents during sizing progress for everlasting development of textile industry and environment-protecting.Chitin and its ramification are thought as green macromolecule materials.At present,chitosan agents are usually used as chitin sizing agents.Chitin sizing agents have many excellent properties, for example,well film forming,good abrasion-resistance,excellent agglutination and appetencies of special fibers.Besides,it has good biodegradation and biologic activity,eminent antibacterial and bacteriostasic activity.These natural maeromolecular polymers fulfill requirement of environment-friendly.Its excellent properties would make it as new green sizing agents in near future.However,chitin's stable chemical structure limits its water solubility.For the time being, the chitosan is prepared by chemical methods.But these methods have many disadvantages,such as width of molecular weight of chitosan,uniformity,energy-wasting and pollution of environment. So,the hydrolyzing method of adopting enzyme do not have any accessory reactions.What is more, the reaction conditions are gentle,and easy to control progress conditions.Therefore,it is very meaningful to study on how to use enzyme to improve the water solubility of sizing agents.This paper studies the method of preparing chitosan with chitin deacetylase(CDA),improving activity of chitin deacetylase(CDA) and degree of deacetylation of chitin ulteriorly based on the former research.Preparing chitin sizing agent after bio-modification,the properties of sizing agent and sized yarns are tested.Based on the resumption training of Aspergillus nidulans that it can produce chitin deacetylase(CDA),the morphology of bacteria is observed.Through the liquid fermentation,the CDA can be prepared.In order to improve the activity of chitin deacetylase(CDA),the training conditions such as training time,temperature,pH value,solution for seed and the inoculation quantity are researched.By experiment,the best liquid fermentation training conditions are sure, detail information as follows:When training time of 96 hours,initial pH value of 6.5,fermentation temperature of 31℃,and inoculation quantity 6%,the activity of enzyme that Aspergillus nidulans prodeces could stabilize in 20-25U/mL.The paper also studies the deacetylation affection of chitin deacetylase after acting on degraded chitin.The enzyme liquid is distilled after fermented,then treated on degraded chitin.The craft conditions such as pH value,acting time,temperature are reviewed.Taking the degree of deacetylation as judging index,orthogonal design experiment is adopted,the optimal process conditions are identified.The chitosan product degree of deacetylation 71.09%could be produced.The paper tested the water-solubility of several modified chitin,which are different from degree of deacetylation:60.75%,63.18%,57.42%,33.33%,47.11%,54.05%,and 50.44%.The final result indicates that the performance of water-solubility will be best when degree of deacetylation are 54.05%and 57.42%.And both degrees are able to dissolve in aqueous solution pH value of 6.5,and which is nearly neutral.It can be concluded that it totally meet requirements of sizing agents in textile industry.This thesis prepares chitin as sizing agent after modification,and tests the properties of sizing performance.Mixed sizing agents are prepared according to a certain mixing ratio.Then compared yarns are sized with certain sizing rate and performance of sized yarns would be tested.Compared with the traditional sizing agent,chitin sizing agent after bio-modification has the excellent performance and has reached sizing requirements of textile industry.