Liquid–crystalline copoly(ester–amide)s prepared from hydroxybenzoic and 4-aminobenzoic acids |
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| Authors: | Wen-Hsin Chen Teh-Chou Chang Fukuji Higashi |
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| Institution: | 1. Department of Chemical Engineering, Chung Yuan Christian University, Chung-Li, Taiwan 32023, Republic of China;2. Department of Polymer Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184, Japan |
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| Abstract: | Copolycondensations of 3,5-dimethoxy-4-hydroxybenzoic (syringic acid, SGA), 4-hydroxybenzoic(PHB), and 4-aminobenzoic (PAB) acids with diphenyl chlorophosphate(DPCP)/LiCl/pyridine were studied. Random copolycondensations of a wide range of monomer compositions afforded copolymers exhibiting birefringence at room temperature. However, when the sequence of PHB and PAB was fixed by using a newly prepared monomer, 4-(4′-aminobenzoyloxy) benzoic acid (PABBA), the ordered copolymers thus prepared showed birefringence above 200°C, but not at room temperature. Variations in solubility and thermal behavior were also observed in randomly and sequentially prepared copolymers. The monomer sequences in copolymers in random copolycondensations could be changed by controlling the reaction of monomers with DPCP. |
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