title: Syntheses of glucomannan esters and their thermal and mechanical properties.
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.
authors.affiliation: Science of Polymeric Materials, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Enomoto-Rogers
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ohmomo
authors.forename: Akio
authors.initials: A
authors.lastname: Takemura
authors.forename: Tadahisa
authors.initials: T
authors.lastname: Iwata
mesh_terms: D060326:Chemistry Techniques, Synthetic; D004952:Esters; D008351:Mannans / Q000138:chemical synthesis* / Q000737:chemistry*; D055595:Mechanical Phenomena; D012997:Solvents / Q000737:chemistry; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D004952:Esters; D008351:Mannans; D012997:Solvents; C022901:(1-6)-alpha-glucomannan
keywords: Acylate; Film; Glucomannan