Abstract
To accelerate the degradation in water of composite resins, samples were stored in boiling water in a pressure cooker for a week and subjected to the tensile test, measurement of the surface roughness and SEM observation. Samples stored in distilled water at 37℃ for one week had decreased tensile strength and lowered equilibrium in Young's modulus, and the physical degradation by water sorption was considered to be caused by this condition. Samples stored in boiling water for one week showed both a decreased tensile strength and in Young's modulus, and the increase of surface roughness. SEM photographs of the fractured surface showed the traces of separation of the filler from matrix resin. The chemical degradation was considered to have been caused in samples stored in boiling water to accelerate the degradation of composite resins in water and the durability of composite resins could be evaluated in a short time by the direct tensile test of samples stored in this condition.
