中文摘要：

通过热失重分析不同稀土氧化物对LLDPE热氧分解行为的影响，并采用氧化诱导期、转矩流变分析方法研究了稀土氧化镧对LLDPE热氧分解行为的影响机理。结果表明：LLDPE的热氧分解温度在添加Eu2O3、Gd2O3、La2O3、Nd2O3、Sm2O3、Yb4O7、Pr6O11、Y2O3、Dy2O3得到提高，CeO2则对LLDPE的起始分解温度没有影响，而加入TbO2、Er2O3、Ho2O3，则使LLDPE的起始分解温度降低。稀土氧化物对LLDPE的热氧稳定的影响可能与稀土元素与氧的配位作用有关，部分稀土氧化物可能通过与氧的配位作用而减缓了氧分子在LLDPE热氧化形成的交联结构中的扩散速度，从而提高了LLDPE热氧稳定性。

英文摘要：

The effect of different rare earth oxides on thermo-oxidative degradation behavior of LLDPE had been studied by thermogravimetry, the mechanism of the effect of lanthanum oxide on LLDPE had also been researched through oxidation induction time （ O. I. T） measurement and rheological analysis. The influences of different rare earth oxides on thermal stability of LLDPE were different. The thermo - oxidative degradation temperature of LLDPE could be improved by the addition of Eu2O3 , Gd2O3 , La2O3 , Nd2O3 , Sm203 , Yb4O7 , Pr6O11 , Y2O3 and Dy2O3 , but be decreased in the case of TbO2 , Er2O3 and Ho2O3, whereas CeO2 had no effect on the initial degradation temperature of LLDPE. The possible explanation for the stabilization effect of some rare earth oxides on thermo-oxidative degradation of LLDPE would be the hindrance of diffusion movement of oxygen molecules in the matrix, owing to the coupling of outer electrons of the rare earth with oxygen.