Molecular Weight Distribution of Irradiated Polymers

Abstract

The molecular weight distribution of irradiated polymers is calculated numerically according to the serial solutions of Saito’s integro-differential equations in relation to crosslinking with or without degradation, and the change in shape of distribution with respect to radiation dose is also discussed. It is shown that the maximum value of weight fraction decreases with increasing radiation dose when crosslinking exceeds degradation. However, when degradation exceeds crosslinking, the maximum value increases with increasing radiation dose, On the other hand, the degree of polymerization corresponding to the maximum value always decreases whether crosslinking may exceed degradation or not. If the initial molecular weight distribution is nearly uniform, a new peak appears at the twice value of the initial degree of polymerization owing to the radiation dimerization.