中文摘要：

文章采用热失重（TG）方法研究氧化镧对不同分子结构聚合物热氧稳定性的影响，并分析了稳定性得到提高的聚合物结构特征。研究表明，氧化镧对不同分子结构的聚合物的热稳定性有不同的影响，它可以催化聚碳酸酯的降解反应，对pET和POM的热氧分解反应没有产生影响，对s-PS的5％失重温度没有影响，但可以使s-PS的50％失重温度提高；PP、POE、HDPE、LDPE、LLDPE等基体的热稳定性可在氧化镧的作用下得到提高，其中POE、HDPE,LDPE,LLDPE四种聚合物的热氧分解温度提高幅度较大，这可能与这四种基体链结构中都含有—CH2-CH2-结构单元有关。氧化镧对HDPE、LDPE、LLDPE的热裂解反应没有产生影响。

英文摘要：

The effects of lanthanum oxide on the thermo-oxidative stability of polymers with different molecular structures were studied with TG method in the paper, and the structure characteristics of the polymers which thermo-oxidative stability has been improved was analyzed. The results showed that the thermo-oxidative stabilities of the filled polymers were related to their main chain structures. The degradation of polycarbonate can be catalyzed by lanthanum oxide, and that of polyethylene terephalate（PET）and polyoxymethylene （POM）were not be affected. The 5 % weight loss temperature of syndiotactic polystyrene（s-PS）was not changed by the addition of lanthanum oxide while the 50 % weight loss temperature could be increased. The thermo-oxidative stabilities of polypropylene （PP）, polyolefin elastomer（POE）, high density polyethylene（HDPE）, low density polyethylene（LDPE）, linear low density polyethylene （LLDPE）could be enhanced by the effect of lanthanum oxide, in which the degree of increase was more remarkable in the polymers such as POE, HDPE, LDPE, LLDPE with--CH2--CH2--structure unit in the main chain. The thermal degradation process of polyethylene was not influenced by adding lanthanum oxide, illustrating that the effect of lanthanum oxide on the thermal stability of polyethylene was closely related to the existence of oxygen.