| abstract |
Polyimides and polyamide-acids having improved solubility and processing characteristics and high glass transition temperatures are provided, having incorporated into the polymeric chain the novel aromatic dianhydride compound 4,4'-bis[2-(3,4-dicarboxyphenyl) hexafluoroisopropyl] diphenyl dianhydride. The polyamide-acids and polyimides are prepared by reacting the 12F-Diphenyl DA with aromatic or aliphatic diamines. It has been found that the polyimides of this invention have improved solubility characteristics, good dielectric properties while at the same time exhibiting relatively high glass transition temperatures, and superior thermal and thermo-oxidative stability. The polymers may be processed into films, fibers or compression molded or fabricated into composites at moderate temperatures and pressures. |