Synthesis and characterization of polyamide‐imides

Abstract

AbstractA series of thermally stable, tough, linear polyimides containing amide linkages was prepared. The new polyamide‐imides were synthesized by reacting a group of isomers of diaminobenzanilide (DABA) with various dianhydrides, such as 4,4′‐oxydiphthalic anhydride (ODPA), 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), and 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride (6FDA). The resulting polyamide‐acids were thermally or chemically converted to the polyamide‐imide (PAI). Twelve polyimides were synthesized from unsubstituted and N‐methyl substituted amide diamines and their properties were compared with previously made polyamide‐imides and the polyimide LARC‐TPI. These polyimides exhibited high inherent viscosities and glass transition temperatures. They were made into tough, flexible films of which some showed good thermal stability and resistance to organic solvents. Overall, the mechanical properties of the PAI films were comparable to those of LARC‐TPI with the 4,4′‐systems exhibiting exceptional properties and crystallinity. These materials have potential as high temperature films, coatings and fibers, as well as molding and laminating resins.