Phase diagram prediction for a blend of Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/epoxy resin during reaction induced phase separation

The phase behavior of a Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/diglycidyl ether of bisphenol A type epoxy (DGEBA)/diethyltoluenediamine (DETDA) blend during reaction induced phase separation is predicted using Flory–Huggins theory. DGEBA and DETDA are treated as a single pseudo-component in order to reflect the crosslinking polymerisation that occurs between them, and both the PPE and the DGEBA/DETDA pseudo-component are treated as polydisperse. The Flory–Huggins χ parameter was determined by measuring the extent of reaction at the on-set of phase separation for different compositions and temperatures and comparing the results with theory. The χ parameter is then used to determine the coexistence curves as a function of conversion of the DGEBA/DETDA pseudo-component, from which the extent of reaction at which vitrification occurs is predicted. The model is shown to be in good agreement with experimental results.