Role of matrix‐particle interface adhesion on fracture toughness of dual phase epoxy‐polyethersulfone blend

Compatibility or miscibility of a polyethersulfone (ICI: Victrex 100P) and a tetrafunctional epoxy (Ciba-Geigy: MY-720), cured with an aromatic anhydride, has been studied using scanning electron microscopy, x-ray microanalysis, and dynamic mechanical spectroscopy. Fracture toughness of epoxy and a blend of epoxy and polyethersulfone has been measured using three point bend tests (ASTM: E-399-81). Fracture surfaces were examined by x-ray microanalysis for detecting concentration of sulfur, present in polyethersulfone, in the matrix and precipitated phase. The influence of the morphology of the epoxy/polyethersulfone blend on its fracture toughness and toughening mechanism has been studied. Fracture toughness values of unmodified and modified cured epoxy resin were evaluated as a function of test temperature.