Fixation Of The Color Of Naturally Colored Domestic Silk With Epoxides

Mulberry silk is a kind of first-class textile material with a long history.The present colored silk fabrics on the market are mainly dyed with synthetic dyestuffs.While the Naturally colored silk(NCS),is an environment-friendly textile material with various colors that endowed by the pigments from mulberry leaves or silkworms,it has unique developing values in many fields.However,because almost all the pigments exist in the sericin layer and they are unstable,the color of NCS could be readily faded during processing or daily use.In order to reserve the pigment and stabilize the color of NCS,an effective way is to reduce the solubility of sericin with crosslinking technology.In this paper,epoxides are used as the crosslinking reagents for stabilizing the color of NCS,the effects of color fixation with different kinds of epoxides are studied,as well as the changes in structure and properties of NCS after crosslinking.Finally,the crosslinking process for NCS fabrics has been promoted so as to obtain higher efficiency.The main results of this study are as follows:(1)Both the polyethylene glycol diglycidyl ether(PEGDE)and glycerin triglycidyl ether(GTE)could obtain good effects on sericin fixation.The optimum reaction conditions for PEGDE were:p H 8.0,PEGDE 3.0 wt%,Ca Cl₂2.0 wt%,50?for 10 h;the optimum reaction conditions for GTE were:p H 8.0,Ca Cl₂3.0 wt%,65?for 4 h.Through quantitative tests and analysis,it is concluded that the color fixing effect of GTE is better than that of PEGDE,and it is speculated that the higher the number of epoxy groups,the better the reaction effect.FTIR spectrogram confirmed the reaction between PEGDE and sericin.The color change of NCS fixated with PEGDE was also studied after repeated home laundering,it proved that the color fastness of the treated NCS was obviously improved compared with the untreated one against repeated home laundering.(2)The structure and properties of NCS before and after fixation were investigated by characterization methods.The results showed the treated NCS was rougher and thicker,it's stability against cooking and repeated home laundering was improved.It's thermal property was barely changed while the antioxidant capacity decreased a lot after the treatment.The sericin fixation had a certain effect on the retention of antioxidant capacity against cooking and repeated home laundering,but it caused decrease in fiber breaking strength,elongation and initial modulus to some extents.The crosslinked NCS fabric showed better performance on wet crease resistant while it's dry crease resistant decreased a lot.The general crosslinking process had little effects on the drape and stiffness of the fabrics.(3)The treatment process on NCS fabrics was improved and the padding-baking method was used,the effect was obvious and the optimum reaction conditions for PEGDE were:PEGDE15.0 wt%,Ca Cl₂4.0 wt%,baking for 17 min with 140?.This method had little effects on tensile property and stiffness,but it improved the wet crease resistant with little decrease on dry crease resistant,and the color fastness of the treated NCS was also improved obviously.