Polycondensation of bismaleimides with aromatic diamines

Summary The polycondensation (Michael addition) of a bismaleimide (BMI, N,N-4,4-[(1-methylethylidene) bis (phenyleneoxyphenylene)] bismaleimide) with an aromatic diamine (DA, 4,4-[1,3 phenylene bis (1-methylethylidene)] bisaniline), in a 1:1 molar ratio, was followed using SEC and FTIR techniques. The polycondensation followed a 2nd-order kinetics with an activation energy, E=51 kJ mol^–1. The mass fraction of dimer varied with conversion following the statistical prediction for an ideal A₂+B₂ polycondensation. At 60% conversion, gelation was observed. This was ascribed to a small advance in the BMI homopolymerization. Thermal degradation took place at T>200 °C. The first step was, possibly, a reversal in the Michael addition reaction as revealed by the decrease in the concentration of CH₂ groups observed in FTIR spectra.This paper is dedicated to Prof. Eloisa B. Mano (IMA, UFRJ, Brazil) for her pioneering work in the development of the polymer field in Latin America.