Effect of structure on thermal behaviour of epoxy resins

The paper deals with the curing behaviour of diglycidyl ether of bisphenol-A (DGEBA) using three novel multifunctional aromatic amines having phosphine oxide and amide–acid linkages. The amines were prepared by reacting tris(3-aminophenyl)phosphine oxide (TAP) with 1,2,4,5-benzenetetracarboxylic acid anhydride (P)/4,4′-(hexafluoroisopropylidene)diphthalic acid anhydride (F)/3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (B). Amide–acid linkage in these amines is converted to thermally stable imide linkage during curing reaction. Curing temperatures of DGEBA were higher with phosphorylated amines than the conventional amine 4,4′-diamino diphenyl sulphone (D). A decrease in initial decomposition temperature and higher char yields were observed when phosphorus containing amide–acid amines were used as curing agents for DGEBA.