Mechanism of secondary crystallization in polymers

In isothermal crystallization of polymers, where the fusion preceding the crystallization process is conducted at relative low temperatures or in samples subjected to γ‐radiation, there is extensive secondary crystallization. Secondary crystallization, which has been found to start stepwise at a time equal to two half‐times of primary crystallization, represents a new process of crystallization following the Avrami equation with n = 1. In addition to this crystallization process a further slow increase of crystallinity with time takes place.