Study On Silk Protein Coating PET Fabric

PET fabric was coated using bioresources macromolecule solution, silk fibroin, sericin and chitosan, and so forth in present study. Through coating moisture absorption, wearing property of PET fabric were improved. By combining merit of PET fabric and nature macromolecule, the newly prepared fabric have the characterization of nature and man-made fibers. This is very important significance to silk-like-finishing of man-made fiber.The preparation of silk fibroin solution and its characteristic were studied in this paper, the result found SF could be dissolved in salt solution, its MW were detected by SDS-PAGE. The results revealed that MW of SF presented with continuous distributing, which concentrated above 20.1kD, no significant difference was found in different salt solutions. SF was also dissolved in H2SO4 solution in different conditions. The SF was separated on gel. The content of the polypeptides with 4.0kD MW were most by using SDS-PAGE. The SF solutions were instable and easily decomposed to low polypeptides and single amino acids.With increase of sulfuric acid concentration, temperature or prolonging of hydrolysis time, total nitrogen, crude protein and amino nitrogen of samples all increased. Some amino acids, like Trp and Ser, were easily destroyed during the hydrolysis. Tyr content was gradually decreased with the increase of hydrolyzing temperature. Gly content was less than Ala during the hydrolysis.The hydrolyzing temperature, sulfuric acid concentration and hydrolyzing time had significantly distinct effect on DH, silk fibroin powder recovery (%) and total amino acid content, however not significantly distinct effect on average polypeptide chain length by Variance analysis. Hydrolyzing temperature and sulfuric acid concentration were more importantly impact factors in the experiment.Molecular weight of sericin prepared at high temperature (120℃) were presented with continuous distributing between 97-40kD, however the MW of sericin prepared at 100℃mostly concentrated above 50kD.The chemical treatment of PET fabric play vital role in coating effect. In this study the chemical treatment with about 8% reduction rate was selected, the concrete condition are as follows: Concentration of sodium hydroxide (NaOH), ethylene diamine, catalyst 1227 were 0.8% (w/w) 20% (v/v), 0.4% (v/v) respectively, water bath at 70℃for one hour. Through chemical eroded reduction treatment of terylene, active groups, such as hydroxyl, amino groups, carboxyl were introduced and generate small cranny or groove on the PET fabric surface, which can make the silk fibroin fix on PET fiber.In the study, PET fabric were coated with SF, SF/CS, sericin, sericin/SF, and using EH as cross-linking agent. The results were as follows, (1) average weight- increasing rate were all more than 8%. (2) Average the residual percentage after hot-water washing of silk fibroin, SF/CS, sericin /silk fibroin coating PET fabric were about 75%, the residual percentage after hot-water washing of sericin was about 70%. (3) Moisture regain of PET fabric coated with four kinds of solution is improved, which is 2.2-3.8 times of non-coated PET fabric. (4) After coating, breaking strength and breaking elongation of PET fabric were improved.(5) Stiffness of different treatment were improved obviously. (6) Thickness of different treatment PET fabric were increased, which was higher 8.82 %-14.71% than non-coated fabric.(7) Breathe freely of different treatment PET fabric had been reduced in different degree.(8) Anti-static properties of different treatment PET fabric were improved. (9) From scan electron microscopy (SEM) images of PET fabric, there were distinctly different of surface characteristic between before and after coated. (10) Characteristic spectrogram of the coating solution appeared in infra-red spectrogram of PET fabric coated.According to the physical-chemical properties, morphological character and molecular structure transformation, the mechanism were analyzed. The physical sorption made the coating fix on fabric; on the other hand, intermolecular force exist between the coating solution and PET fabric, the force can increase the crystal degree of protein, which make the structure convert from amorphism conformation intoβ-sheet conformation . This provided the science foundation for developing new functional fabric by using bioresources macromolecule, such as silk proteins.