Abstract
A detailed investigation on the effects of catalysts on the curing of maleimide resins was conducted using model compounds. N-phenylrnaleimide (PMI) and N, N'-diphenylaspartimide (API) were selected as model compounds.
Without catalyst, PMI was polymerized at a temperature more than 200°C because of slow polymerization rate, and the product was PMI polymer (peak molecular weight by GPC=66,000). On the other hand, in the presence of API, the polymerization of PMI was accelerated a little but the product was PMI oligomer (peak molecular weight =1,000).
Imidazole catalyst (2-ethyl-4-methyl-imidazole) accelerated the polymerization of PMI at 170°C but the product was PMI oligomer (peak molecular weight=1,000) independent of the presence of API.
The catalytic effect of dicumyl peroxide (DCP) was hindered by API. Increasing of API caused lowering the polymerization rate of PMI and the molecular weight of PMI polymer.
The knowledge obtained by model reactions corresponds with the curing behaviour of maleimide resins.
