Effect on the toughness and adhesion properties of epoxy resin modified with silyl-crosslinked urethane microsphere

In order to give a toughness and improve adhesion properties of the cured e poxy system, modified epoxy resins, which have prereacted urethane microsph eres formed using dynamic vulcanization method in liquid diglycidylether of bisphenol A, were prepared. It was found that the size of the particles de creased to sub-micro order with increase in solubility of urethane oligomer s in epoxy resin, and coefficient of variance in the particle size distribu tion resulted in less than 15%. Fracture energy G(1c) of the cured system w as highly improved. Lap shear strength and peel strength were also im roved . These mechanical and adhesion properties do not depend on any curing cond ition of epoxy resin because of the existing stable particles in the epoxy resin before curing. (C) 2001 Published by Elsevier Science Ltd.