Abstract
The investigation was made on the deterioration mechanism of aged silk fabrics, those were treated in various ways. When we studied on the deteriorated silk fibroin by thermal analysis and amino acid analysis, it was found that the decomposition temperature of aged silk was higher than that of the recent one, and amino acid in amorphous region of aged silk was reduced more than that of crystalline region. Therefore, the degree of crystallinity of silk fibroin increased relatively as long as it is aged. Moreover the decomposition temperature of silk treated with γ-rays was lower than that of the untreated one, and all amino acids in crystalline and amorphous regions were reduced without distinction. Amino acid analysis of coagurated silk fibroin in silkgland by heat treatment showed that the amino acids were reduced remarkably over 300 t in air, reduction of tyrosine and phenylalanine in amorphous region were less in nitrogen gas.
