COMPOSITIONS OF AROMATIC POLYBENZIMIDAZOLES AND AROMATIC POLYIMIDES OR AROMATIC POLYETHERIMIDES

摘要

Novel miscible compositions comprising from about 1 part by weight to about 99 parts by weight of an aromatic polyimide or polyetherimide and from about 99 parts by weight to about 1 part by weight of an aromatic polybenzimidazole. Preferably, the composition comprises from about 5 partg by weight to about 95 parts by weight of an aromatic polyimide or polyetherimide and from about 95 parts by weight to about 5 parts by weight of an aromatic polybenzimidazole. In a composition mostly comprised of an aromatic polybenzimidazole, it is preferred that the aromatic polyimide be thermoplastic and that it or the aromatic polyetherimide be present in the composition in an amount sufficient to make the aromatic polybenzimidazole more processable for molding purposes and also less susceptible to moisture. More preferably, such compositions are comprised of from about 65 parts by weight to about 95 parts by weight of an aromatic polybenzimidazole and from about 35 parts by weight to about 5 parts by weight of a thermoplastic aromatic polyimide or polyetherimide. Most preferably, such compositions are comprised of at least about 10 parts by weight of the aromatic thermoplastic polyimide or aromatic polyetherimide. In a composition mostly comprised of a soluble, thermoplastic aromatic polyimide or aromatic polyetherimide, it is preferred that the aromatic polybenzimidazole be present in an amount sufficient to render the soluble thermoplastic aromatic polyimide or aromatic polyetherimide less sensitive to solvents, and to increase the glass transition temperature of the aromatic polyimide or polyetherimide. Preferably, the aromatic polybenzimidazole is present in such compositions in an amount sufficient to result in a composition with greatly enhanced solvent resistance. More preferably, such compositions are comprised of from about 65 parts by weight to about 95 parts by weight of a soluble thermoplastic aromatic polyimide or aromatic polyetherimide and from about 35 parts by weight to about 5 parts by weight of an aromatic polybenzimidazole. Most preferably, such compositions should contain at least about 25 to 30 parts by weight of a polybenzimidazole in order to render the soluble thermoplastic aromatic polyimide or aromatic polyetherimide component much more resistant to solvents at room temperature. In addition to improving solvent resistance, greater amounts of aromatic polybenzimidazole in the composition substantially increase the glass transition temperature of the composition. Phase-separated compositions may be formed from the miscible compositions by heating a composition above its binodal or spinodal phase boundary temperature or glass transition temperature to cause it to phase separate and then quickly quench-cooling it to freeze the phaseseparated morphology. The novel compositions are useful under severe environmental conditions. The compositions have good impact resistance, enhanced solvent resistance and generally good price-performance characteristics.