Toughening of Epoxy Adhesives with Predispersed Modified Sebs

Abstract

In this study we tried to disperse saturated styrenic block elastomer SEBS in an epoxy matrix instead of unsaturated nitrile rubber. It was supposed to be possible by the choice of a mixture of solvents such that one is a good solvent for both the polystyrene block (PSt) and rubber block (R) of the SEBS and also for the epoxy resin (Ep); and the other is a good solvent for the polystyrene (PSt) block and the epoxy resin (Ep), but not for the rubber block (R) and has a higher boiling temperature than the former. Thus it is expected that at the first stage of evaporation the SEBS or preferably its EB block separates succeedingly does the Ep matrix which mixed with PSt block by the possible phenyl interaction. It is not known whether such a stepwise separation of phases did occur or not in practice, but the resulting sol-like mixture and the cured adhesive showed the structure and properties as expected.