茂金属聚乙烯的结构与性能研究

【作者】 仲伟霞；

【导师】 华幼卿； 毛立新；

【作者基本信息】 北京化工大学 ， 高分子材料， 2001， 硕士

【摘要】 本论文以六种茂金属聚乙烯和LDPE、LLDPE、HDPE三种传统聚乙烯树脂作为研究对象，借助GPC、FTIR、WAXD、DSC、ARES、密度梯度仪以及万能试验机等现代化测试手段，系统研究了茂金属聚乙烯的结构与性能，同时对于茂金属聚乙烯的加工应用也作了初步探索。 通过对茂金属聚乙烯和传统聚乙烯的分子链结构(分子量及其分布、相对支化度)、结晶结构、力学性能以及流变性能的深入研究，发现茂金属聚乙烯结构规整，分子量分布窄，这一方面使茂金属聚乙烯的力学性能明显优于传统聚乙烯，另一方面亦使其加工性能远不如传统聚乙烯，其中mPE-5的加工性能较差，而mPE-3由于分子中引入部分长支链结构，使其剪切粘度对频率和温度的敏感性得到显著提高，故其加工性能较好；另外，通过将茂金属聚乙烯与传统低密度聚乙烯共混吹膜实验，发现少量低密度聚乙烯的掺入，不仅能够在一定程度上改善茂金属聚乙烯的加工性能，而且所得薄膜力学性能亦较好。这些结果对于茂金属聚乙烯的分子设计和应用研究提供了重要的基础数据。更多还原

【Abstract】 The Structure and properties of six metallocene polyethylenes and three traditional polyethylenes were studied by means of GPC, FTIR, WAXD, DSC, ARES, density and tensile tests respectively, while the processing application of metallocene polyethylenes was also investigated primarily.Based on the intensive study of chain structure ( molecular weight and its distribution, branching degree, etc. ), crystalline structure, mechanical properties and rheological properties of polyethylenes, it was found that the uniform structure and narrow molecular weight contribute a lot to the excellent mechanical properties and the poor processibility of metallocene polyethylenes. Among the six metallocene polyethylenes, mPE-5 exhibit poor processibility, while the melt viscosity of mPE-3 was sensitive to both frequence and temperature, which primarily due to the introduction of long chain branches ( LCBs ) to its main chain and do good to its processibility. By addition, the processibility of metallocene polyethylenes could be improved through blending them with a little part of traditional LDPE, and the mechanical properties of result films were also well. All the above results would provide important database to the molecular design and application study of metallocene polyethylenes.更多还原