EFFECT OF PREPARATION METHOD OF POWDERED SILK ON THE MECHANICAL-PROPERTIES OF MOLDED SILK

The physical properties of moulded silk were influenced by the propert ies of fibroin powder. Very little breakage was observed in the moulde d silk made from silk fibroin treated with calcium chloride. When trea ted with sulfuric acid, however, the amorphous region of fibroin was d amaged and highly crystalline powder was produced. Longer treatment wi th sulfuric acid damaged the crystalline part, decreasing the strength of the moulded silk. Treatment with sulfuric acid for 2 h was most su itable for silk moulding. The strength of moulded silk was high when t he fibroin powder contained 8% water. Treatment for 30 min at 120-degr ees-C under a pressure of 750 kg cm-2 were the optimum conditions.