中文摘要：

采用DSC研究了稀土化合物氧化镧、硬脂酸镧对LLDPE（线性低密度聚乙烯）非等温结晶行为的影响。随着氧化镧和硬脂酸镧浓度的增加，LLDPE的结晶度出现下降的趋势。氧化镧可起到并相成核的作用，使LLDPE的结晶速率增快，冷却结晶峰向高温移动，而硬脂酸镧没有改变结晶峰的位置，对结晶速率没有影响。广角XRD（X射线衍射）结果显示氧化镧和硬脂酸镧没有使LLDPE的晶型产生变化，但在有氧化镧的体系中，LLDPE在110和200晶面的晶粒尺寸有明显增大。力学实验显示，氧化镧使LLDPE的拉伸强度略有降低，断裂伸长率则有较大幅度的下降。硬脂酸镧对LLDPE的拉伸强度影响不大，却使断裂伸长率有大幅度提高。

英文摘要：

The crystallization and mechanical properties of LLDPE and its blends with La2O3 and lanthanum stearate were studied with DSC, wide angle X - ray and tensile measurement. The crystallization rate of LLDPE could be increased by the heterogeneous nucleation effect of La2O3 while the same phenomenon didn＇t occur in the case of lanthanum stearate. The crystallinity declined in both blends of LLDPE with La2O3 and lanthanum stearate when the concentration of fillers increased. Wide angle X -ray results show no new crystalline form appeared in the composites, but the crystallite dimensions in 110 and 200 reflections increased in the case of L%O3. The tensile strength of LLDPE decreased slightly and the elongation to break decreased distinctly with the addition of L%03, while in the case of lanthanum stearate, the tensile remained almost the same but the elongation to break improved remarkably.