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本文研究了冷却速率、结晶温度和熔体温度等因素对聚丙烯β相结晶得到的试样的熔融行为的影响。发现β晶型熔融峰的面积随冷却速率的降低或结晶温度的升高而增加。在低于300℃的温度下,熔体温度对聚丙烯的β相结晶无影响。300℃以上的高温破坏了聚丙烯β相结晶的晶核,冷却结晶时不再生成β相晶体。测定了α相及β相球晶在123—140℃的温度范围内线性增长速率,发现在140℃以下,β球晶的增长速率大于α球晶。研究了β相结晶动力学,发现聚丙烯β相结晶不符合Avrami方程,而要用不完全球晶结晶的动力学理论来描述。
In this paper, the effects of cooling rate, crystallization temperature and melt temperature on the melting behavior of the samples obtained by crystallization of polypropylene β phase were studied. It was found that the area of the beta crystalline melting peak increases with decreasing cooling rate or with increasing crystallization temperature. At temperatures below 300 ° C, the melt temperature has no effect on the β-phase crystallization of polypropylene. The high temperature above 300 ℃ destroys the crystal nuclei of the β-phase of polypropylene, and the β-phase crystal is no longer formed during the cooling crystallization. The linear growth rate of α and β spherulites in the temperature range of 123-140 ℃ was measured. The growth rate of β spherulites was found to be greater than α spherulites below 140 ℃. The β-phase crystallization kinetics was investigated and it was found that the β-phase crystallization of polypropylene did not conform to the Avrami equation and was described by the kinetic theory of incomplete spherulites.