Impact Properties and Fracture Mechanism of Epoxy Resin Filled with Irregular-Shaped Alumina Particles

Abstract

The effect of particle size distribution on the impact properties of epoxy resin filled with irregular-shaped alumina particles was studied using an instrumented Charpy impact tester. For this purpose, the alumina particles were prepared by crushing fused α-Al 2 O 3 having a wide size distribution and a mean size of about 10 μm were sorted by air-separation. Particles having narrow size distribution and mean size of about 5 - 7 μm were obtained. The absorbed impact energy by the narrow distribution particle-filled resin was higher than that of the wide distribution particle-filled resin and was almost the same as that of unfilled cured epoxy resin. In general, the impact strength of filled epoxy resins is less than that of unfilled ones. From the result above, controlling the particle-size distribution seems to be one effective technique which improves many mechanical properties without decreasing the impact strength. Observations of the fractured surfaces of specimens were made in order to estimate the mechanism above, using scanning electron microscopy.