Self-toughening of epoxy resin by introduction of highly crosslinked thermoset epoxy microspheres

Abstract

The theories and technologies concerning polyolefin toughening with rubber or inorganic rigid particle have been studied comprehensively, the results indicated that the toughening with rubber always lowers the modulus and heat resistance of materials. Also, toughening with inorganic rigid particle is not good because of its low dispersion and miscibility with epoxy resin. Monodisperse epoxy microspheres (EMs) with high crosslinking density were prepared with Polypropylene glycol with molecular weight of 600 as the reaction solvent and trifunctional epoxy resin (TDE-85) and aromatic diamine (DETDA) as the precursors. The formation of EMs was investigated in detail. The crosslinked microspheres were used as toughening agent to realize DGEBA/DDS system self- toughening. When adding 5wt% epoxy microspheres, the impact strength improved by 87% and Tg increased more than 6 °C. The results show that the prepared epoxy microspheres with high crosslinking density can not only greatly improve the toughness of epoxy resin, but also improve its heat resistance.