Enhanced Charpy impact strength of epoxy resin modified with vinyl‐terminated polydimethylsiloxane

ABSTRACT This article deals with enhancement of the toughness of epoxy resin (ER) based on diglycidyl ether bisfenol A by either polydimethylsiloxane (PDMS) or vinyl‐terminated polydimethylsiloxane (VT‐PDMS). To improve the compatibility of these two phases, dicumylperoxide (DCP) was used as a compatibilizer. It was established that only specific composition of the components can lead to enhancement of ER toughness without significant reduction of storage modulus, T g , and interphase adhesion. The highest impact strength was recorded for ER with VT‐PDMS (10 wt %) and DCP (2 wt %) due to increased interfacial compatibility between two phases, which was proved by 1 H NMR and dielectric spectroscopy. Critical ductile brittle transition occurring between 10 and 15 wt % of rubber was observed by both morphological and dynamic mechanical analysis studies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45720.