Cure behavior and thermal degradation mechanisms of epoxy and epoxy-cyanate resins

The cure reactions of tetraglycidyl methylene diamine (TGMDA) epoxy cured w ith tetrasubstituted aromatic diamine on one hand and diglycidyl ether of b isphenol A and diglycicyl ether tetrabromobisphenol A epoxies cured with me thylene bis (phenyl-4-cyanate) on the other hand are reported. Systematic F ourier transform infrared (FTIR) spectroscopy studies of the cure reaction of epoxy and epoxy-cyanate during thermal cycles are presented. FTIR studie s indicate that the reaction of TGMDA monomer is total but the network cont ains a large amount of primary amine. The cyanate monomer reacts rapidly to form triazine structures. Then the epoxy monomers homopolymerize and cross link with free cyanate groups. The gas chromatography/mass spectrometry stu dy of volatile products evolved during the polymer thermal degradation show s the dehydration of the epoxy network and the decomposition of the amine s tructure. The FTIR and solid-phase C-13 nuclear magnetic resonance analysis revealed that the ether functions and the amine groups are temperature sen sitive but the triazine structure is not. Copyright (C) 1999 John Wiley & S ons, Ltd.