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Synthesis of Liquid-Crystalline Polymer Containing Coumarin Moieties by Photopolymerization  

Lee, Jong-Back (Department of Chemical Engineering, Dongeui University)
Lee, Kwang-Hyun (Department of Chemical Engineering, Dongeui University)
Kang, Byung-Chul (Department of Chemical Engineering, Dongeui University)
Publication Information
Elastomers and Composites / v.45, no.4, 2010 , pp. 286-290 More about this Journal
Abstract
Liquid-crystalline (LC) monomer, which was functionalized with a coumarin group on their extremity, was synthesized by UV light irradiation in their LC phases. LC monomer was converted into the dimers by the cycloaddition reaction of the coumarin group, and the LC phases were maintained after photodimerization reaction. The dimers showed LC phases in the wider temperature range than those of the corresponding monomer. Structures of the compound were identified by FT IR and $^1H$ NMR spectroscopies. Their phase transition temperatures and thermal stability were also investigated by differential scanning calorimetry (DSC), gel permeating chromatography (GPC) and polarized optical microscopy (POM). From optical polarizing microscopy, the prepared polymer shows enantiotropic liquid crystallinity with smectic and nematic textures.
Keywords
photodimerization; coumarin group; UV light; liquid crystalline; DSC; GPC; POM;
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