Synthesis And Application Of The Derivant Of Silk Peptide

Silk peptide and sericin, obtained from silk protein which has been treated by someparticular processes, possess abundant and a great variety of amino acids, so they havevery promising applications. Silk peptide, as the natural resource of amino acids, can beused to synthesize a series of ecological surfactants applied in industry and our daily life.What’s more, silk peptide and sericin, as the environment-friendly finishing agents, canalso be used in the textile functional finishing. Therefore, Silk peptide and its derivantsare one of the research hotspots.Silk peptide-based surfactant was synthesized by making silk peptide to react withlauroyl chloride. The alkali which controls the pH value of the reaction system and thesolvent were discussed. The influence of NaOH and K₂CO₃, acetone andtetrahydrofuran on the structure composition of the product were compared. The resultsshow that The content of amino acids of the product was higher, which was29.8412%when K₂CO₃was used as the alkali and acetone was used as the solvent. The structureof the surfactant synthesized was characterized by IR. The surface activity of thesurfactants synthesized at different conditions was determined. The result shows that thesurface activity of product was better when K₂CO₃was used as the alkali and acetonewas used as the solvent, at which the critical micelle concentration （CMC） was1.83g/L,and the γCMCwas25.60mN/m.Silk peptide and sericin were applied to wool fabric by using the biological TGenzyme as the crosslinking agents. The results indicate that TG enzyme could catalyzesilk peptide and sericin to graft onto the mercerized wool, result in the weight incrementof wool. When the dosage of TG enzyme was12%o.w.f. and the dosage of sericin was200%o.w.f., the weight growth percentage of unwashed wool and wool washed oncewere8.70%and4.30%, respectively. When the dosage of TG enzyme was12%o.w.f.and the dosage of silk peptide was150%o.w.f., the weight growth percentage ofunwashed wool and wool washed by once were4.80%and3.15%, respectively.The surface morphology and the amino acid content of the wool fiber untreated and treated by the silk peptide and sericin catalyzed by TG enzyme were tested by SEMand Amino Acid Analysis. We could see that there were silk peptide and sericin particlesat the surface of the mercerized wool fiber from the SEM graph. What’s more, thecontents of glutamic acid and lysine of the grafted wool increased obviously. Thepercentage compositions of glutamic acid and lysine of the sericin-grafted woolimproved from18.07to19.22, from2.90to3.17, respectively. And the percentagecompositions of glutamic acid and lysine of the silk peptide-grafted wool improvedfrom18.07to19.87, from2.90to3.15, respectively.The changes of whiteness, moisture regain, capillary effect of the wool fabricgrafted by silk peptide and sericin treated by TG enzyme were measured. The resultsindicate that after the action of TG enzyme, the whiteness of the wool didn’t havedistinct change, while the moisture regain and the capillary effect both increased further.When the dosage of sericin was200%o.w.f., the moisiture regain rised from9.6644%to9.8795%, and when the dosage of silk peptide was150%o.w.f., the moisture regainrised to9.8613%.The changes of permeability, moisture penetrability and tensile breaking strengthof the grafted wool fabric treated by TG enzyme were measured, too. The results showthat the permeability decreased slightly, while the moisture penetrability and tensilebreaking strength increased. When the dosage of sericin was200%o.w.f., the moisturepenetrability of the grafted wool increased from2671.91g/dï¹'m^-2to2764.78g/dï¹'m^-2.When the dosage of silk peptide was150%o.w.f., the moisture penetrability of thegrafted wool reached to2779.59g/d m^-2.When LS-710acted as the crosslinking agent, the wool fabric was also grafted bysericin and silk peptide. The concentration of LS-710was chosen at40g/L. When thedosage of sericin was80%o.w.f., the weight growth percentages of the unwashed wooland the wool washed by once were7.79%and5.54%, respectively. When the dosage ofsilk peptide was80%o.w.f., the weight growth percentages of the unwashed wool andthe wool washed by once were6.14%and5.15%, respectively.The grafted wool fiber treated by LS-710was tested by SEM, and from the SEMgraph, we could see that there were fairly dense sericin and silk peptide particles on theexternal surface of wool.The changes of whiteness, moisture regain, capillary effect, permeability, moisture-penetrability and tensile breaking strength of the wool fabric grafted by silkpeptide and sericin treated by LS-710were measured. The results indicate that thewhiteness of wool after treated also didn’t show any clear difference, while the moistureregain, capillary effect, permeability and moisture-penetrability all reduced. At the sametime, the tensile breaking strength of the wool fabric treated increased.