The experimental results on the abnormal melting of crystallized raw rubber by Wood and Bekkedahl are theoretically studied. The effect can be explained by the fact that the relaxation time for the thermal expansion of the crystalline particles differs from that of the amorphous particles. At the point where the melting begins, the time interval of observation becomes comparable to the relaxation time of amorphous particles. The point will become higher when the time rate of heating increases, and also when the relaxation time itself becomes larger. The point at which the melting completes itself is determined by the relaxation times of amorphous and crystallized state, heating rate and previous history. This effect will become remarkable at a suitable heating rate, and will be more remarkable in natural rubber than vulcanized rubber.
抄録全体を表示