Strictly alternating copolymers containing parabanic acid and amide or imide moieties

Abstract

Abstract1,3‐Bis(4‐aminophenyl)imidazolidinetrione dihydrochloride (1) was synthesized and used as starting material for the synthesis of strictly alternating copolymers. Fully aromatic copolymers containing parabanic acid and amide moieties (7a, b) were found to exhibit high glass temperatures and good thermal stability. Meltable copolymers with parabanic acid and amide moieties (7d–j) could be obtained by introducing flexible aliphatic spacers. The use of an unusually short, but symmetrically branched spacer was particularly effective. The strictly alternating, thermally stable copolymer 10 was synthesized from 1 and pyromellitic dianhydride. By using the trimethylsilyl ester of polyamic acid 11, the imidization temperature could be lowered by 100°C.