Preparation and liquid-crystalline properties of toluene-4-sulphonyl urethane of hydroxypropylcellulose
作者:
M.H. Godinho,
J.P. Borges,
J.C. Bordado,
M.T. Cidade,
A.F. Martins,
期刊:
Liquid Crystals
(Taylor Available online 1993)
卷期:
Volume 14,
issue 3
页码: 653-659
ISSN:0267-8292
年代: 1993
DOI:10.1080/02678299308027744
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
A novel liquid-crystalline polymer, the toluene-4-sulphonyl urethane of hydroxypropylcellulose (TSUHPC), was prepared through chemical modification of hydroxypropylcellulose (HPC) ofMw= 60000 g mol−1. The resulting polymer was characterized by infrared spectroscopy, differential scanning calorimetry (DSC) and polarizing microscopy. It was found that thermotropic liquid crystal phases are formed between about 60°C and 110°C. Concentrated solutions of TSUHPC in acetone andN,N-dimethylacetamide exhibit cholesteric behaviour, at room temperature. When approaching the lyotropic mesophase to solid transition, either by cooling or by solvent evaporation, very interesting arborescent structures of a seemingly fractal nature may be observed, depending on the kinetics of the transition. A banded texture can be observed when the polymer is sheared near the transition to the isotropic phase.
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