Improving the toughness of epoxy with a reactive tetrablock copolymer containing maleic anhydride

Abstract

ABSTRACTReactive block copolymers (BCPs) provide a unique means for toughening epoxy thermosets because covalent linkages provide opportunities for greater improvement in the fracture toughness (KIC). In this study, a tailored reactive tetrablock copolymer, poly[styrene‐alt‐(maleic anhydride)]‐block‐polystyrene‐block‐poly(n‐butyl acrylate)‐block‐polystyrene, was incorporated into a diglycidyl ether of bisphenol A based epoxy resin. The results demonstrate the advantage of reactive BCP in finely tuning and controlling the structure of epoxy blends, even with 95 wt % epoxy‐immiscible triblocks. The size of the dispersed phase was efficiently reduced to submicrometer level. The mechanical properties, such as KIC, of these cured blends were investigated. The addition of 10 wt % reactive BCP into the epoxy resins led to considerable improvements in the toughness, imparting nearly a 70% increase in KIC. The designed reactive tetrablock copolymer opened good prospects because of its potential novel applications in toughening modification of engineering polymer composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42826.