Cure and physical properties of thermoplastic modified epoxy resins based on polyethersulfone

Abstract

AbstractDielectric, mechanical, thermal, rheological, and electron microscopy measurements are reported for five series of thermoplastic modified amine cured epoxy resin systems. The epoxy and thermoplastic components have been systematically changed to investigate the factors affecting the phase separation process. Data reported cover both changes in the physical properties occurring during cure and also of the final cured matrix. Dielectric data obtained from fully cured materials exhibits a Maxwell–Wagner–Sillers relaxation process characteristic of a phase separated morphology. Correlation of dielectric relaxation and electron microscopy data indicates that the phase structure changes with the thermoplastic content and composition of the epoxy phase. The mechanical properties change significantly at about 20–25% (w/w) of incorporated thermoplastic, coincident with the formation of a cocontinuous phase morphology. © 1995 John Wiley & Sons, Inc.