对氯化镁/乙醇载体进行了物理脱醇、化学脱醇并负载TiCl4得到球形聚乙烯催化剂,利用XRD,TG,SEM等方法对载体的物理脱醇过程进行了表征,考察了物理脱醇过程对催化剂性能的影响.表征结果显示,未脱醇的氯化镁/乙醇载体中,氯化镁和乙醇之间存在多种络合方式,载体外表面光滑无孔,随乙醇含量的逐渐降低,载体逐渐出现孔道和片层状结构.随着载体醇含量的降低,催化剂的钛含量和活性逐渐降低,聚乙烯粉料的熔体流动指数也逐渐降低.采用真空热脱醇法时,即使载体的醇含量相同,但由于批次不同,所制备的球形聚乙烯催化剂也可能性质不同.因此,真空热脱醇法不具备工业化应用的价值,直接使用化学脱醇法,可有效提高球形催化剂的批次稳定性.%The spherical adducts of magnesium chloride/alcohol were dealcoholized by physical or chemical method,and then spherical polyethylene catalysts were synthesized through supporting titanium tetrachloride on the dealcoholized adducts. The physical dealcoholization process was characterized by means of XRD,TG and SEM to investigate its influence on the performances of the catalysts. The results showed that there were several coordination modes between magnesium chloride and alcohol in the adducts without dealcoholization. The surfaces of the original spherical adducts were smooth and nonporous,but,with decreasing the alcohol content,pores and lamellar structure gradually appear on the surfaces. With decreasing the alcohol content in the spherical adducts, the Ti content and activity of the catalysts and the melt indexes of the PE powder products gradually decreased. Under the vacuum-thermal dealcoholization,the different batches of spherical adducts with the same alcohol content could not be used to synthesize the catalysts with the same properties. So,the vacuum-thermal dealcoholization do not possess the industrialization value. The batch stability of the spherical catalysts can be improved effectively by using chemical dealcoholization.
展开▼
