Thermotropic Polyarylates Containing High Proportions of Rigid 4, 4'-Biphenylene Moieties in the Main Chains

• Published in: KOBUNSHI RONBUNSHU Vol. 48; no. 12; pp. 759 - 763
• Main Authors: TABATA, Norikazu, INOUE, Toshihide, GOTO, Noriaki, TANAKA, Tatsundo
• Format: Journal Article
• Language: Japanese
• Published: The Society of Polymer Science, Japan 01.01.1991
• Subjects: 4'-Hydroxybiphenyl-4-carboxylic Acid; 4, 4'-Biphenylene Moiety; 4, 4'-Diphenyldicarboxylic Acid; As-Spun Fiber; Heat Treatment; Injection Molded Test Pieces; Thermotropic Polyarylate
• ISSN: 0386-2186; 1881-5685
• DOI: 10.1295/koron.48.759

Thermatrapic liquid crystalline polyarylates containing high proportions of rigid 4, 4'-biphenylene moieties in the main chains were prepared from 4'-hydroxybiphenyl-4-carboxylic acid (HBCA), 4, 4'-diphenyldicarboxylic acid, and some substituted hydroquinones. To prepare the polyarylates with 50 mol% HBCA by melt-polymerization, the substituents of substitued hydroquinone had to be bulky one such as phenyl group. As-spun fibers of these polyarylates showed high moduli of 56.4-81.0 GPa. Injection molded test pieces from one of these polymers showed a flexural modulus of 43.8 GPa (0.8 mm thickness). On heat treatment of such test pieces, the flexural modulus increased to 51.7 GPa. SEM observations showed that the shapes of fibrils were changed, and X-ray diffraction revealed that the crystal size and chain orientation increased by the heat treatment.