Syntheses of glucomannan esters and their thermal and mechanical properties

详细信息    查看全文

• 作者：Yukiko Enomoto-Rogers ; Yusuke Ohmomo ; Akio Takemura ; Tadahisa Iwata
• 关键词：Glucomannan ; Acylate ; Film
• 刊名：Carbohydrate Polymers
• 出版年：30 January, 2014
• 年：2014
• 卷：101
• 期：Complete
• 页码：592-599
• 全文大小：1920 K

文摘

Fully substituted glucomannan (GM) acylates with acyl carbon numbers (n) of 2, 3, 4, 5, 6, 8, 10, and 12 were prepared from konjac GM (KGM) in carboxylic acid/trifluoroacetic anhydride (TFAA). GM acetate acylates (n = 3, 4, 5, 8, 12, 16, and 18) were prepared from KGM in acetic acid/carboxylic acid/TFAA. Differential scanning calorimetry (DSC) and X-ray diffraction revealed that the GM esters did not exhibit melting peaks and reflections derived from crystal, indicating they were amorphous. The glass-transition temperatures (T_gs) of the GM esters tended to decrease with increasing acyl carbon number, ranging from 174 掳C for GM acetate (GMAc) to 64 掳C for GM laurate (GMLa). Colorless and transparent GM ester films were obtained by solvent casting and thermo-pressing. The mechanical properties of the GM ester films were controlled by the acyl group structure.