Thermotropic liquid crystalline aromatic-aliphatic polyimides—5. Preparation and properties of homo- and copoly(imide-carbonate)s based on benzophenonetetracarboxylic diimide and biphenyl units

✍ Scribed by Moriyuki Sato; Tomohiro Hirata; Tomoaki Kamita; Ken-Ichi Makaida

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 567 KB
• Volume: 32
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(95)00196-4

✦ Synopsis

Melt polycondensation of N,N'-bis(3-hydroxypropyl)-

or N,N'-bis(6-hydroxyhexyl)benzophenonetetracarboxylic diimide (n = 3 and 6) and/or 6,6'-(4,4'-biphenylylenedioxy)dihexanol with propylene or hexamethylene bis(pheny1 carbonate)s (m = 3 and 6) afforded new semi-rigid homo-and copoly(imide-carbonate)s. The monomers for the polymerization, dihydroxyalkyl derivatives of imides, were prepared by a two-step reaction via intermediates, diacetates, from tetracarboxylic dianhydrides and 3-aminopropyl-or 6-aminohexylalcohol. The structures of the expected monomers and polymers were confirmed from FTIR and 'H-and "C-NMR spectrum measurements and elemental analyses. Thermotropic liquid-crystalline (LC) properties of the polymers were evaluated by differential scanning calorimetry (DSC), polarizing microscopy and powder X-ray analyses at various temperatures. These measurements indicated that most polymers except for a copolymer with a propylene segment (m = 3) based on the benzophenonetetracarboxylic diimide of a hexamethylene spacer (n = 6) and the biphenyl unit showed birefringent melts. Only the copolymer having a hexamethylene spacer (n = 6) and a propylene segment (m = 3) formed a well-defined nematic LC phase. Measurements of viscoelasticity with a thermomechanical analyzer showed that the poly(imide-carbonate)s possessed good mechanical properties.