Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7792992 | Carbohydrate Polymers | 2014 | 8 Pages |
Abstract
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 (Tgs) of the GM esters tended to decrease with increasing acyl carbon number, ranging from 174 °C for GM acetate (GMAc) to 64 °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.
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Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Yukiko Enomoto-Rogers, Yusuke Ohmomo, Akio Takemura, Tadahisa Iwata,