Synthesis and properties of PMR type poly(benzimidazopyrrolone-imide)s

PMR type poly(benzimidazopyrrolone-imide)or poly(pyrrolone-imide)(PPI) matr ix resin was synthesized using the diethyl ester of 4,4 '-(hexafluoroisopro pylidene)diphthalic acid (6FDE), 3,3 ' -diaminobenzidine, para-phenylenedia mine, and monoethyl ester of cis-5-norbornene-endo-2,3-dicarboxylic acid (N E) in anhydrous ethyl alcohol with N-methylpyrrolidone, The homogeneous mat rix resin solution (40-50% Solid) was stable for a storage period of 2 week s and showed good adhesion with carbon fibers, which ensured production of prepregs. The chemical and thermal processes in the polycondensation of the monomeric reactant mixture were monitored by Fourier transform infrared sp ectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, etc. Thermosetting PPI as well as short carbo n fiber-reinforced polymer composites was accomplished at optimal thermal c uring conditions. The polymer materials, after postcuring, showed excellent thermal stability, with an initial decomposition temperature > 540 degrees C. Results of MDA experiments indicate that the materials showed > 70-80% r etention of the storage modulus at 400 degreesC and glass transition temper atures as high as 440-451 degreesC. (C) 2001 John Wiley & Sons, Inc.