B. Sapich, J. Stumpe, T. Krawinkel
Jan 31, 1998
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0
Influential Citations
71
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Quality indicators
Journal
Macromolecules
Abstract
Two dicarboxylic acids were prepared by alkylation of 4-hydroxycinammic acid with 1,6-dibromohexane or 1,12-dibromododecane. The dichlorides of these dicarboxylic acids were polycondensed with mixtures of isosorbide and methylhydroquinone. All copolyesters then obtained showed nematic schlieren textures. Furthermore, three dicarboxylic acids were synthezised by alkylation of 4-hydroxycinammic acid with the ditosylates of di-, tri-, and tetraethylene glycol. Numerous copolyesters were prepared from the dicarboxylic acids and mixtures of isosorbide with methyl-, tert-butyl-, or phenylhydroquinone. Also 2,7-dihydroxynaphthalene was used as a comonomer. Almost all resulting copolyesters were cholesteric, and nearly 50% of them were capable of forming a Grandjean texture. The photochemical behavior of selected copolyesters was studied in solution in spin-coated films and in films with Grandjean texture. Depending on the reaction conditions, photo-cross-linking by 2 + 2 cycloaddition competed more or less succe...