Study On Polyacrylonitrile-grafted Modification Technology Of Cashmere Fiber

Cashmere products prone to pilling and felting due to the scale structure outside the cashmere fiber.Traditionally,various treatments are applied to the fabric surface to solve these problems.In this research,a new method was proposed:the cashmere fiber was modified directly by chemical grafting method,and the scales were covered by polymer,so as to achieve the purpose of anti-pilling and anti-felting.In this search,various conditions of the graft reaction were respectively investigated when initiated by two different initiate systems:system A consists of ammonium persulfate and sodium bisulfite,and system B consists of hydrogen peroxide and ferrous ammonium sulfate.And then,the fiber after modification was evaluated.（1）Respectively,the following factors were investigated to probe the effluences on grafting efficiency,namely,the monomer concentration,reaction temperature,reaction liquor ratio,and the amount and the redox ratio of initiator,pH of the reaction system,reaction time.When initiated by system A,the most significant factor on the graft reaction is the monomer concentration,and when initiated by system B,the most important three factors in order for the monomer concentration,reaction temperature,and the reaction liquor ratio.（2）Both of the initiate systems initiated grafting of acrylonitrile onto cashmere effectively.The optimal condition under system A were:monomer concentration 0.4 mol?L^-1,liquor ratio 140,reaction temperature 60℃,pH of 5,ammonium persulfate in an amount of monomer concentration of 5.79%,redox ratio 1.5,reaction time 60minutes.The graft efficiency was 63.70%under the optimal conditions.The optimal condition under system B were:hydrogen peroxide in an amount of monomer concentration of 12.03%,ferrous ammonium sulfate in an amount of monomer concentration of 1.41%,and the redox ration of 8.5:1,the reaction temperature 70℃,pH of 7,monomer concentration 0.5 mol?L^-1,the optimal reaction time was 60 minutes,liquor ratio 108.The graft efficiency was 96.12%under the optimal conditions.（3）Two new absorption peaks of 2243cm^-1 and 1465cm^-1 in the infrared spectrum of the modified fiber appears to prove the success of grating acrylonitrile,SEM photographs showed that the scales outside the modified cashmere fiber tend to be smooth,mechanical test results showed that the breaking strength of the modified fiber significantly increased while the breaking elongation decreased slightly,and the thermal stability was improved after modification.The grafting efficiency of modified fiber,initiated graft reaction by system B,fell only 3.40%,indicating good stability.（4）Compared with traditional methods,the chemical reactions of chemical graft modification reacts directly on the surface of the cashmere fiber,thus the improving effect of the scale structure is more durable than the conventional methods,the breaking strength of the fiber is significantly increased by the introduce of the strongly polar Cyano,the Cyano can complex metal ions,which provids new ideas as well as the foundation for the latter study on improving the antistatic properties of the cashmere fiber.