The New Method To Recycle Sericin And The Application Of Sericin In Textile

Silk,often named "queen-fiber",is a top grade fiber.In our country the mount of silk fiber is very large.The yield of silk was 87.8 thousand tons in the year of 2005,93 thousand tons in the year of 2006.Without scouring,the purpose of which is degumming,silk fiber can't be used in garments directly.About 20-30%mass of silk is sericin,which not only have effect on handle and luster of silk,but also have effect on dyeing and finishing afterwards,so it is necessary to be degummed.Took the ratio of degumming as 20%to count,about 17.5 thousand tons in 2005,18.6 thousand tons in 2006 of sericin were degummed from silk fiber.All of the sericin was discharged with waste water;it is not only a pollution of environment,but also a big waste of nature protein. Being a nature protein,sericin can be used in many fields,such as textile,medicine,and foodstuff, cosmetic and so on.Therefore,it is very meaningful to study the recycling of sericin,and there have been many methods of recycling sericin,such as acidification method,flocculation,organic solvent method,centrifuging method,membrane filtration method,and freeze method and so on. However,all of these methods can't be used in industrial.So,it is necessary to look for a new recycling method.The principle of recycling sericin in this paper is:degumming of silk fiber is in alkaline condition,so the sericin is under its PI with negative charge after degumming.Because anion exchange fiber with positive charge has electrostatic pull to sericin,it can adsorb sericin from solution.Then marinating or eluting the anion exchange fiber with acetic acid,the negative charge of adsorbed sericin is neutralized or turns into positive charge and the interaction force between anion exchange fiber and sericin turns into electrostatic repulsion.So the sericin adsorbed by the anion exchange fiber desorbs into solution.An assembling sericin can be got. In order to detect the concentration of sericin solution truly,four spectrophotometries (coomassie breiliant blue G250 visible spetrophotometry,light green SF(yellowish)visible spetrophotometry,congo red visible spetrophotometry,UV spetrophotometry)were studied.And the virtue & defect of these spetrophotometry were also compared.Finally,UV spetrophotometry was selected in this paper because of its convenience.Viscose fiber was selected as the substrate in this paper to prepare anion exchange fiber. The cationization technology and exchange capacity of anion exchange fiber were studied.The optimum condition for cationization got via experiment:temperature 90℃,time 40min, concentration of activator 5%(o.w.f).And the degree of cationization increased with the increasing of electrolyte concentration of reaction system.During the research of recycling sericin used anion exchange fiber,the different adsorbent models of sericin to anion exchange fiber at different adsorbent temperature were found. At the adsorbent temperature of 25℃and 50℃,they matched Freundlich muti-molecule adsorption models,while at the adsorbent temperature of 75℃,it matched Langmuir uni-molecule adsorption model.And at low concentration of sericin,the adsorption quantity increased with the increasing of adsorbent temperature.During the desorption of sericin which had adsorbed to anion exchange fiber,the optimum condition for desorption was found:acidity 6.8g/L,temperature 75℃, time 120min,liquor ratio 1:40.At last the sericin was used in functional finishing of cotton fabric.Found that it could form a layer of protein on the surface of viscose fiber,which had the function of health care.At the same time,the fabric had coolness after washing.