| Mulberry silk is a kind of natural protein fiber, which is mainly composed of 70-80% fibroin, 20-30% sericin, a little bit of waxiness and mineral. The fibroin is utilized after the processing of silk reeling, weaving, scouring and dyeing, however, the most of sericin is disposed along with the waste water during the cocoon cooking and the silk degumming processes. The output of raw silk in china is about 60-90 thousand tons every year, about 20-30 thousand tons of sericin protein is running off with the waste water. This can not only cause the wasting of the sericin protein but also can lead to the environmental pollution problem. Data has shown that it is well known that sericin has been used in such fields as textile, hygiene, pharmacy, food, health care and cosmetic and so forth. In my opinion, there will be a broad prospect in sericin application and the demand of sericin will be larger and larger in the future. Therefore, the study on the sericin recovery from the silk scouring waste water is done first in this thesis, and then, the modification manufacturing and finishing of polyester fabrics and cotton fabrics using sericin is studied. Blaze, as the waste material in the silk manufacturing, is normally useless, but there is much sericin on it (about 40-46%), which is useful in the manufacturing of rabbit hair knitted fabrics. A little bit of blaze can be blended together with the rabbit hair, wool and polyamide. After carding, spinning, winding and knitting, the knitted fabrics are steamed for a short period of time, at the same time, the sericin on the blaze swells, melts and coheres the rabbit hairs. The relative movements among fibers could be restricted so that the quantity of rabbit hair losing and the water shrinkage of the knitted fabrics made of rabbit hairs could be reduced greatly. In order to assure the long-lasting effect of sericin treatmeant, the technique of the sericin fixation is studied, anda relatively ideal fixing effect is obtained.1. Study on the sericin recoveryAccording to the properties of sericin and the waste water after silk scouring, the recovery methods as acid separating, icing and ultrafiltering are mainly studied. A feasible recovery method and a satisfactory recovery effect are obtained. The processing line is as follows.The waster water is treated by pretreatment, acid separating, still separating, dialyzing, dring into sericin products. The clear sericin liquid obtained from still separating is then treated by ultrafiltering, evaporating and concentrating, dialyzing, dry into sericin products. The clear water after ultrafiltering can be discharged or partly recycledThe waster water after sericin recovery is then treated by biological treatment, BOD5 and CODcr in the anaerobic pool are decreased by 30~40% and 80% respectively. BOD5 and CODcr in the aerobic pool are all decreased by 80-90%. The quality of the discharged water after treatment can be controlled within the national standards, and can be recycled partly. The problem of environmental pollution is resolved and some power energy can be saved in this way.2. Study on the modification finishing of the polyester fabric by using sericinThe hygroscopicity and antistatic property of the traditional polyester fabric is worse. A new way to improve the hygroscopicity and antistatic property of polyester fabrics is proposed and many experiments and researchare done., The best technical condition are obtained by using the orthogonaltesting methods, which are temperature 90 °C , time 60min, sericin concentration 2%. The influencing order of factors in sericin treatment is sericin concentration, temperature, time. After sericin treatment, the hygroscopicity and antistatic property have been improved greatly. The capillary effect value is increased by 30%, the static voltage is decreased from2000v to lOOOv, the half-decay time is decreased from 3s to Is. The decreasing amplitude is up to 50% and 67% respectively. After being processed, other comfortable properties of polyester fabrics have been improved a little too.3. Study on the modification finishing of pure cotton fabrics by using sericinThe levelness of the pure cotton fabric after being washed is very poor, it often needs to be ironed. A new method to improve the levelness of pure cotton fabrics after being washed by using sericin is proposed and many experiments and research are done. The best technical conditions are obtained by using the orthogonal testing methods, which are temperature 90 °C, time 60min, sericin concentration 2%. The influencing order of factors in sericin treatment is sericin concentration, temperature, time. The levelness of the pure cotton fabrics after being washed has been improved from 1 grade to 3. After being processed, other comfortable properties of pure cotton fabrics have been improved a little too.4. Study on the manufacturing of rabbit hair knitted fabrics by blending a little bit of blazeThe fiber losing quantity and water shrinkage of traditional rabbit hair knitted fabrics are higher. A new method to decrease both the fiber losing quantity and the water shrinkage of rabbit hair knitted fabrics is bring forward, which is a little bit of blaze(about 40-46% of sericin on it) can be blended together with the rabbit hair, wool and polyamide. After carding, spinning, winding and knitting, the knitted fabrics are steamed for a short period of time, at the same time, the sericin on the blaze swells, melts and coheres the rabbit hairs. The relative movements among fibers could be restricted so that the quantity of rabbit hair losing and the water shrinkage of the knitted fabrics made of rabbit hairs could be reduced greatly. In this thesis, six kinds of yarns and knitted fabrics are manufactured with different material component and the vary kinds oftechnical parameters are studied. Under the condition of steaming temperature100°C, the water shrinkage of fabrics processed in different times are compared and a conclusion that 10 minutes of steaming and 10% of blaze are the best plan is obtained. The sericin on the blaze can stick the rabbit hairs andcan not affect the fabrics handle. The fiber losing quantities of the rabbit hairknitted fabrics being treated by steaming has been decreased from 46.07% to 74.93%. The water shrinkage of the rabbit hair knitted fabrics being treated by steaming can be controlled from 1.7% to 0.2%, decreased from 64.58% to 91.67% compared with the fabrics without steaming. This indicated that the knitted fabrics made of rabbit hairs, blaze, wool and polyamide have better fiber losing proof effect and shrinkproof effect.5. Study on the fixation of sericin by glutaraldehyde In order to assure that the effects of the fabrics being processed by sericin can last a long time, the sericin on the fabrics must be fixed. In this thesis, after the different fixing methods are discussed and analyzed, glutaraldehyde is selected as fixing agent for the reason of environment protecting. All the factors such as the concentration of glutaraldehyde, the pH value of the solution, the treatment temperature and time are studied in detail and a satisfactory fixing effect is obtained.for polyester and the cotton fabrics, the best technical conditions are attained by using orthogonal testing method, which are the concentration of 1%, the temperature of 50 °C, the time of 90min. The fixing fastness is increased with the increasing of glutaraldehyde concentration which is better less than 1% in order that the color of the fabrics are not changed obviously. With the increasing of the temperature, the fixing fastness is increased too, but the best temperature should be about 50°C in order to avoid the sericin being hydrolyzed. The fixing effect is satisfactory by using glutaraldehyde as the fixing agent and the effect can hardly be changed with the increasing of the washing time.For the rabbit hair knitted fabrics, in order to overcome the staining phenomena and omit the bleaching processing, all the factors such as the glutaraldehyde concentration, the temperature and the time are studied in details and the optimized technics which are glutaraldehyde concentration 0.1%, sodium sulphate 0.1%, rongalite 0.5%, temperature 50°C and time 90min is obtained at last. The processing passages is reduced and the cost is decreased in this way, the rabbit hair knitted fabrics after being fixed by glutaraldehyde has good shrink-proof and hair shed proof effect.For many reasons, the largest sericin concentration is 2% in the modification tests. Whether the effect will be more perfect or not when a higher concentration is used is left for further research.Summarizing that mentioned above, a new plan for silk mills to solve the problems of the sericin recovery and waster water treatment is proposed. At the same time, the modification finishing methods for both polyester and cotton woven fabrics are obtained according to the sericin characters. And a new way to decrease both the fiber losing and the water shrinkage of rabbit hair knitted fabrics is bring forward. This research result has a important significance in environmental protecting, sericin application, increasing the added value of textiles and so on and it will have a large spreading foreground of industrialization and can bring high blooded economic and social benefits.
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