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A linear-chained epoxy resin was formulated from phenyl glycidyl ether and nadic methyl anhydride catalyzed by benzyldimethylamine. Intermolecular polymerizations were modeled as a parallel set of propagation reactions. Fourier-transform infrared spectroscopy was used to determine the concentrations of the oxirane, anhydride, and ester moieties within the resin as a function of time for two isothermal cures. Data analyses yielded the propagation rate constant as a function of temperature and the initiator's concentration, including contributions from impurities within the resin. Results compared favorably with measurements on fractionated resins, using gel permeation chromatography. Population density distributions are described by Poisson molar distributions for this resin.

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Subject to intermolecular addition and intramolecular cross-linking reactions, deterministic models which describe chain infrastructure for a random A4 + B2 resin and a Poisson-type, chain-initiated epoxy anhydride thermoset were derived. Sol fractions are described in terms of molar concentrations of molecules of a given chemical composition and conversion and in terms of branch node distributions. Moments of the population density distribution form conditionally convergent series. Two limits were selected. Their difference is proportional to the substance in the gel. Purely deterministic derivations are made regarding the internal structure of the gel-structural parameters related to rubber elasticity, for example, which have been previously held to be obtainable only by statistical arguments. Numerical solutions are presented graphically to emphasize the distinct molecular structure within the two resins and the consequence with regards to mechanical performance. Deterministic solutions are equal to solutions derived by expectation theory.