Curing and thermal behaviour of epoxy resin in the presence of aromatic imide-amines

Abstract

The paper describes the synthesis and characterization of aromatic imide-amines obtained by reacting pyromellitic dianhydride (P)/or benzophenone 3,3′, 4,4′-tetracarboxylic dianhydride (B) (1 mol) with excess of 4,4'-diaminodiphenyl ether [E]/or 4,4′-diaminodiphenyl methane [M]/or 4,4′-diaminodiphenyl sulfone [S] and their use as curing agents for diglycidyl ether of bisphenol-A (DGEBA). Structural characterization of imide-amines was done using FTIR, ¹H-NMR,¹³C-NMR spectroscopy and elemental analysis. These aromatic imide-amines were used as curing agents in order to investigate the effect of structure on the curing and thermal behaviour of diglycidyl ether of bisphenol-A (DGEBA). Curing behaviour of DGEBA in the presence of stoichiometric amounts of aromatic imide-amines was investigated by differential scanning calorimetry (DSC). A broad exothermic transition in the temperature range of 180-230°C was observed in all the samples. The peak exotherm temperature (<i style="">T</i>_p) was lowest in case of imide-amines based on B and M and highest in case of imide-amines based on P/or B and S. Thermal stability of the isothermally cured resins was investigated using dynamic thermogravimetry in nitrogen atmosphere. The char yield was highest for resin cured with imide-amines based on B and E.