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本文用差示扫描量热法测定了3种稀土氧化物对聚丙烯等温结晶行为的影响。结果表明,Avrami方程指数n、成核机理、晶体生长方式以及结晶晶型基本上不受稀土氧化物的影响。少量稀土氧化物可使结晶晶格垂直于分子链方向单位面积的界面自由能降低,结晶速率加大,其中Y_2O_3的效果最为显著,La_2O_3效果最低,混合稀土的作用效果与Y_2O_3相似。填加1wt%的Y_2O_3可使聚丙烯的结晶速度常数增大一个数量级。
In this paper, the effects of three kinds of rare earth oxides on the isothermal crystallization behavior of polypropylene were determined by differential scanning calorimetry. The results show that the Avrami equation index n, nucleation mechanism, crystal growth mode and crystalline form are basically unaffected by rare earth oxides. A small amount of rare earth oxides can reduce the free energy per unit area of the crystal lattice in the direction perpendicular to the molecular chain and increase the crystallization rate. The effect of Y_2O_3 is the most significant, while the effect of La_2O_3 is the lowest. The effect of mixed rare earth is similar to that of Y_2O_3. Addition of 1wt% Y_2O_3 can increase the crystallization rate constant of polypropylene by one order of magnitude.