Curing of epoxy-amine systems: The topological model of polyaddition producing branched macromolecules

Results are presented of modeling in terms of statistical topology of the initial stages of polyaddition run in a hypothetical epoxy-amine system, which products branched macromolecules. The system included a diepoxy compound and a primary amine. Estimates are given for the probability of formation of the following three types of compounds: (i) linear compounds, (ii) branched oligomers (including various topologically equivalent compounds), and (iii) macrorings (Table 1). About 180 reactions were considered, representing possible routes to topologically individual oligomers. For simplification, primary and secondary amines were assumed to be equally reactive. The molecular weight distribution was characterized in relation to the extent of reaction (up to 70% conversion of epoxy groups). In further calculations, a model including a diglicydyl resorcin ether and m-phenyl-diamine was used. Selected properties of the curing systems (functional groups content, refractive index, surface tension, average molecular weight, viscosity, molar volume) are calculated in relation to the extent of reaction of epoxide groups (Figs. 3-5). The courses of the relationship obtained appear to be consistent in type with whose of well-known experimental data.