茂金属催化线性低密度聚乙烯的光氧化稳定性  

Photo-oxidation Stability of Metallocene Catalyzed Linear-Low Density Polyethylene

作　　者：房海霞[1] 叶永成[1] 白福臣[1] 

机构地区：[1]中国科学院长春应用化学研究所,长春130022

出　　处：《应用化学》2005年第2期164-167,共4页Chinese Journal of Applied Chemistry

摘　　要：茂金属催化线性低密度聚乙烯(m-LLDPE),传统Ziegler- Natta线性低密度聚乙烯(LLDPE)和低密度 聚乙烯(LDPE)氙灯光氧化不同时间后,用红外光谱法和力学性能测试对降解过程中的力学性能和化学结构 的变化进行跟踪测试。实验结果表明,光氧化后聚乙烯的支化度和结晶度都有所增大,亚乙烯基双键浓度逐 渐降低,末端乙烯基双键浓度由于NorrishⅡ型反应增强而增大。与辛烯共聚LLDPE相比,乙烯 己烯共聚 m-LLDPE由于亚乙烯基双键的浓度较高而光稳定性较差,2种乙烯 辛烯共聚m-LLDPE的光稳定性与共聚单 体相同的LLDPE的光稳定性相似,LDPE的光稳定性高于所有的LLDPE。The films of linear-low density polyethylenes made with metallocene catalyst and Ziegler-Natta catalyst respectively and low density polyethylene, were irradiated with a Xenon lamp for various time to examine their photo-oxidation stability. The mechanical property and chemical structure changes occurred during the photo-oxidation process were studied by mechanical property measurement and FTIR spectroscopy. The results show that both the branching degree and crystallinity of polyethylenes increase after photo-oxidization. The concentration of vinylidene decreases gradually with the prolongation of irradiation time, while that of end-vinyl increases due to NorrishⅡ reaction. Ethylene-hexene copolymerized m-LLDPE is more inclined to be photo- oxidized than ethylene-octene copolymerized LLDPE due to the higher concentration of vinylidene in the former. The photo-oxidation stability of the other two ethylene-octene copolymerized m-LLDPEs is comparable to that of LLDPE with the same comonomers. The oxidation rate of LDPE studied in the paper is slower than those of all the LLDPEs.

关 键 词：茂金属线性低密度聚乙烯 Ziegler-Natta线性低密度聚乙烯 光氧化降解 

分 类 号：O631.2[理学—高分子化学]