Aromatic/cycloaliphatic polyimides and polyamide-imide from trans-1,4-cyclohexane diisocyanate: Synthesis and properties

Mixed aromatic/alicyclic polyimides were prepared by polycondensation reactions of trans-1,4-cyclohexane diisocyanate (CHDI) with pyromellitic dianhydride (PMDA), benzophenonetetracarboxylic dianhydrid (BTDA), and hexafluoroisopropylidene diphthalic anhydride (6FDA). Also, polycondensation of CHDI with trimellitic anhydride led to synthesis of polyamide-imide. In order to obtain the optimized condition for polymerization reactions, model compound studying was considered. Model compound and polymers mere characterized by common methods. Physical properties of polymers, including thermal behavior, thermal stability, solution viscosity. and solubility behavior, were also studied. Mild polymerization condition was the main advantage of using diisocyanate instead of diamine in synthesis of these thermally stable polymers. Furthermore, synthesis of poly(amic acid) and polyimide via nonaromatic diamine can introduce synthetic problems, but by applying nonaromatic diisocyanate a facile method for preparation of aromatic/cycloaliphatic polyimides was obtained. (C) 2000 John Wiley & Sons, Inc.