中文摘要：

Phillips催化剂（CrOx/SiO2）是一种重要的高密度聚乙烯工业催化剂。以钛改性硅胶作载体,制备钛改性铬钼复合Phillips催化剂（CrMo/TiSi）,并考察其对乙烯聚合的催化性能。对比铬钼复合催化剂（CrMo/Si）,运用程序升温还原（TPR）、X射线光电子能谱（XPS）和密度泛函理论（DFT）计算等方法考察钛改性对铬钼双金属相互作用的影响。乙烯聚合活性和产品性能表征结果表明,钛改性后催化剂活性提高,聚乙烯分子量增大,分子量分布变宽。乙烯/1-己烯共聚产物的高温凝胶渗透色谱、高温（13C-NMR、升温淋洗分级和连续自成核退火热分级（TREF＋SSA）结果表明,钛改性复合催化剂有利于1-己烯插入,产物中高分子量部分支链含量减少。

英文摘要：

Phillips catalyst（CrOx/SiO2）is an important industrial high density polyethylene catalyst.In this work,a Ti-modified Cr-Mo hybrid Phillips catalyst（CrMo/TiSi）was prepared and tested to improve the ethylene polymerization performance.CrMo/TiSi and CrMo/Si catalysts were compared and studied by the temperature-program reduction,X-ray photoelectron spectrometer and density function theory.Due to the Ti-modification,the reduction peak shifted to the lower temperature and the binding energy of the Cr species increased,which reflected that the Cr species were easier to be reduced.The ethylene polymerization performances over the CrMo/TiSi and CrMo/Si catalysts at different conditions were investigated.The Ti-modification increased the activity and the catalyst produced the polymer with higher molecular weight（MW）.Determined by high temperature 13C-NMR,the copolymer by the Timodified catalyst exhibited higher 1-hexene incorporation.However,the amount of short chain branches for the copolymer decreased in the high MWpart,according to the temperature rising elution fractionation cross successive self-nucleation and annealing（TREF＋SSA）results.