THERMAL-DEGRADATION OF POLY(BISMALEIMIDES)

In the reported experiments, the thermal decomposition of poly(bismaleimides) has been investigated by using programmed and isothermal thermogravimetric analysis (TGA) in nitrogen. Reaction rates and overall activation energies were calculated from isothermal weight loss studies. For five aliphatic poly(bismaleimides) a linear correlation between the activation energies and the number of methylene groups in the sequence between the maleimide residues was found. Aliphatic poly(bismaleimides) follow first-order kinetic law up to a conversion of 60 - 70% having activation energies between 196 and 256 kJ/mole. Poly(2,4-bismaleimidotoluene) which was found to have in highest polymer decomposition temperature (PDT) did follow the first-order kinetics up to a conversion of 60% in contrast to other aromatic poly(bismaleimides). In addition to the TGA, the pyro-field ion mass spectra of the polymers were recorded and are discussed.