Solid-state polymerization of maleimide by 2,2′-azobisisobutyronitrile

The solid-state polymerization of maleimide by 2,2′-azobisisobutyronitrile was studied over the temperature range 65–85°C. The polymerization was carried out either by heating the solid mixture of maleimide and 2,2′-azobisisobutyronitrile or by heating the two compounds separately in twin ampules. The results of the kinetic study showed that the lifetime of the propagating radicals was short and that the rate of termination was proportional to the mole amount of propagating radicals. The ESR spectrum showed that stable radicals that were not main propagating radicals were in the polymerizing system.