On the crystal structure and thermal property of lyophilized fibroin

DOI JASI Web Site

Bibliographic Information

Other Title
  • 凍結乾燥フィブロインの結晶構造と熱的性質について
  • トウケツ カンソウ フィブロイン ノ ケッショウ コウゾウ ノ ネツテキ セイシツ ニ ツイテ

Search this article

Abstract

On the lyophilized samples prepared by different methods from fibroin aqueous solutions, which extracted from posterior section of silk gland and prepared from raw silk by Cu-En method, the crystaline structures and the thermal properties were investigated. The following results were obtained:<br>1) On the fibroin samples, which prepared by lyophilization of fibroin aqueous solution water-extracted from posterior section of silk gland and by lyophilization of fibroin precipitated from the same solution, the conformations of these samples were fl-structures and the positions of the amide I lay 1650 and 1630cm-1. The decomposition temperatures were observed at 318-320°C and the thermodecomposition began at lower temperature than other samples and were stepwise.<br>2) The fibroin sample, which was prepared by lyophilization of fibroin aqueous solution prepared from degummed silk by Cu-En method, was amorphous and the band of the amide I appeared at 1660cm-1 and the decomposition temperature was 305°C. The broad and weak endothermic peak in the thermogram was observed about 180-230°C and at this temperature the X-ray diffraction pattern changed to that of β-structure and the band of the amide I appeared newly about 1630cm-1.<br>3) The fibroin sample, which prepared by lyophilization of the alcohol-precipitate from the aqueous solution of degummed silk by Cu-En method, gave an X-ray diffraction pattern of β-structure, and the amide I was observed about 1650 and 1630cm-1, and the sample thermodecomposed at 315°C. The lyophilized fibroin precipitated with ammonium sulfate gave X-ray diffraction pattern of α-structure, and the position of amide I was at 1645cm-1 alone. The thermodecomposition temperature was 310°C and the transconformation to β-structure by heating did not occured.<br>4) On the IR-spectra of degummed silk, the positions of the amide I were observed about 1660 and 1630cm-1 and the sample decomposed at 350°C. The spectra was similar that of the lyophilized fibroin except the absorption band about 1700cm-1.<br>Generally, on the change of IR-spectrum by heating, the absorption band about 1700cm-1 occured with elevating temperature and the intensities of the amide II and amide III decreased remarkably about thermodecomposition.

Journal

Details 詳細情報について

Report a problem

Back to top