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本文认为处于非晶态的链段总浓度是高聚物结晶过程的推动力;二次结晶阶段实验数据偏离Avrami方程的原因是球晶碰撞后使可供结晶过程进行的晶体总表面积的减少。据此,导出了能描述包括二次结晶阶段在内的修正了的Avrami方程。用90—130℃范围内测得的聚丙烯等温结晶动力学曲线,以及PET的解偏振、DSC结晶动力学曲线进行了验证,实验结果与理论曲线吻合。显微摄影证明了实验数据偏离Avrami方程时,球晶间开始接触。
In this paper, we consider that the total concentration of non-crystalline segments is the driving force behind the crystallization process of polymer. The reason for deviation of experimental data from Avrami equation in the secondary crystallization stage is the reduction of the total surface area of the crystal available for the crystallization process after collision of spherulites. Based on this, we derive a modified Avrami equation that describes the secondary crystallization stage. The isothermal crystallization kinetics curves of polypropylene measured in the range of 90-130 ℃, the depolarization of PET and DSC crystal kinetics curves were also validated. The experimental results are consistent with the theoretical curves. Micro-photography proves that when the experimental data deviate from the Avrami equation, the spherulites begin to contact with each other.