REACTION OF A DIEPOXIDE WITH A DIISOCYANATE IN BULK .1. USE OF A TERTIARY AMINE CATALYST

Reactions between a diepoxide and a diisocyanate can lead to copolymers having two kinds of heterocycles in their chemical structure: isocyanurate rings which are the result of the reaction of three isocyanate functions with themselves and oxazolidone rings which are the result of the reaction of an epoxy function with an isocyanate function. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) were used in order to understand the influence of a catalyst, like a tertiary amine, on the reaction mechanism of polymer formation. We also observed the influence of the stoechiometric ratio between the diisocyanate and the diepoxide on the glass-transition temperature of the obtained network. We have identified the nature of the exotherms observed in DSC experiments and proposed an assignment of the different peaks observed in the FTIR spectra. We showed that the amount of catalyst and the stoechiometric ratio between the diisocyanate and the diepoxide strongly influence the structure of the final polymer and its thermal characteristics such as the glass-transition temperature. © 1990 Springer-Verlag.