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Characterization of polymer‐brush‐type polysaccharide β‐ketoesters
Author(s) -
Yoshida Yutaka,
Isogai Akira
Publication year - 2008
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.28283
Subject(s) - pullulan , polymer chemistry , chemistry , tetrahydrofuran , polymer , alkyl , polysaccharide , cellulose , amylose , lithium chloride , random coil , organic chemistry , starch , stereochemistry , circular dichroism , solvent
Abstract Polyvinyl alcohol (PVA) and four glucans, cellulose, curdlan, amylase, and pullulan, were dissolved in 8% lithium chloride/1,3‐dimethyl‐2‐imidazolodinone, and reacted with ketene dimers with long alkyl or alkenyl chains under homogeneous conditions. The corresponding polysaccharide β‐ketoesters with degrees of substitution (DS) of 2.1–2.9 and the PVA β‐ketoester with DS 0.9 were prepared in the yields of 80–90%. Solution‐state 1 H‐ and 13 C‐NMR spectra of the polysaccharide and PVA β‐ketoesters revealed that the polymer chains behaved like solid even in solutions. However, size‐exclusion chromatographic analysis showed that the polysaccharide and PVA β‐ketoesters prepared had random‐coil conformations in tetrahydrofuran, which could not explain the anomalous NMR patterns. The specific chemical structures of the substituents having long and branched alkyl or alkenyl chains may have brought about such specific solution‐state NMR patterns, irrespective of the chemical structures of the polymer backbones. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008