General Features of Crystalline Polymers

Most crystalline polymers with metylenic groups in their structure and with a degree of crystallinity below 50% present a sub-glass relaxation whose intensity and location scarcely differ from those observed for the amorphous polymer in the glassy state. The temperature dependence of this relaxation follows Arrhenius behavior, and its activation energy is of the same order as that found for secondary processes in amorphous polymers. 

Annealing promotes crystallite thickening at the expense of the crystalline-amorphous interphase and the amorphous phase. This process decreases the intensity of the glass-rubber relaxation and enhances that of the a relaxation if the crystalline polymer develops this absorption. 

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