Abstract
The fracture toughness and thermal shock resistance of an epoxy resin filled with alumina particles as a hard filler and CTBN rubber particles as a soft filler were investigated by focusing on the surface treatment of alumina particles. Although the fracture toughness was improved by filling alumina particles and CTBN rubber particles, the contribution of the alumina surface treatment to the fracture toughness was small. The thermal shock resistance was improved by filling CTBN rubber particles. However, the effect of alumina particles was not always positive. The thermal shock resistance is generally improved by the surface treatment of alumina particles : it was an example that the improvement was attained in the case of the brittle matrix epoxy resin regardless of the existence of CTBN. But on the other hand, the treatment was not effective in a tougher matrix resin. The fracture mechanisms were discussed, based on the fractographic observations.
