Epoxy-bismaleimide systems: network development and structure, and effect of these on water interactions and thermal-oxidative stability

The kinetics and mechanism of curing of a multicomponent thermosetting system based on tetraglycidyl-4,4' diaminodiphenylmethane (TGDDM) and N,N'-bismaleimido-4,4'diphenylmethane (BMI), cured in the presence of 4,4'-diaminodiphenylsulfone (DDS), has been investigated by Fourier transform infrared (FTIR) spectroscopy. It has been shown that two chemically distinct networks are formed upon curing, the one being due to the homopolymerization of BMI and the other to the addition reaction between TGDDM and DDS. Dynamic-mechanical measurements suggested that, despite the different growing rates of the two networks, they are highly interpenetrated and form a single phase, molecularly homogeneous system. [Continues.]