The cure mechanism of the 4,4'-(N,N'-bismaleimide)diphenylmethane-2,2'-diallylbisphenol A system

Some kinetic features of reactions occurring at 140-200 degreesC in equifun ctional actual and model systems (phenylmaleimide-2,2'-diallylbisphenol A a nd phenylmaleimide-2-allylphenol) were studied by the techniques of IR and H-1 and C-13 NMR spectroscopy. The equifunctional conversion of maleimide a nd allyl groups yielding a I : I addition product takes place in this tempe rature range. The mechanism of the reaction involving monofunctional reacta nts differs from that of the cure of the actual system because of steric hi ndrances in 2,2'-diallylbisphenol A, which retard reversible Diels-Alder re actions, and different reactivity of maleimide groups. It was found that th e only side reaction in the system of interest is the dehydration of phenol ic groups that necessarily involves the 1:1 adduct as a reactant.