氧化镧对LLDPE热氧化分解行为的影响

 通过热失重、氧化诱导期、流变分析和热重-红外联用分析等方法研究了氧化镧对LLDPE热氧分解行为的影响。在添加氧化镧后，LLDPE的5%和50%失重温度可大幅提高。进一步的研究表明, 氧化镧的存在并不能阻止LLDPE在热氧分解时的氧化反应和交联反应。在LLDPE的初始分解阶段，氧化镧的存在不改变分解所形成的产物，但氧化镧对LLDPE高温阶段的断链反应有抑制作用。这可能是由于氧化镧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，从而阻碍了交联链的热氧分解反应和断裂。

Effect of Lanthanum Oxide on the Thermo-oxidative Degradation Behavior of LLDPE

The effect of lanthanum oxide on thermo-oxidative degradation behavior of LLDPE was studied by thermogravimetry, oxidation induction time measurements, rheological and TG-FTIR analyse. With addition of lanthanum oxide, the temperature at 5% and 50% weight loss can be dramatically enhanced. The results indicated that the oxidation reaction and the crosslinking reaction of LLDPE during its thermal oxidation could not be inhibited by lanthanum oxide. The TG-FTIR results showed the products of thermo-oxidative degradation of LLDPE in the initial stage did not chang in the presence of lanthanum oxide, however, the chain scission reaction in the high temperature could be hindered. The possible explanation for the stabilization effect of lanthanum oxide 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.