铁系催化剂/烷基铝体系生成双峰聚乙烯聚合机理的研究  

THE MECHANISM OF FORMING BIMODAL POLYETHYLENE BY BIS（IMINO） PYRIDYL IRON（Ⅱ） PRECATALYST WITH TRIETHYLALUMINUM

作　　者：王世波[1] 刘东兵[1] 毛炳权[1] 

机构地区：[1]中国石油化工股份有限公司北京化工研究院聚烯烃国家工程中心,北京100013

出　　处：《高分子学报》2013年第9期1172-1176,共5页Acta Polymerica Sinica

摘　　要：对2,6-双[1-（2,4,6-三甲基苯亚胺）乙基]吡啶二氯化铁（1）/三乙基铝（TEA）催化体系在不同条件下的乙烯聚合性能进行了研究,分别考察了不同聚合反应温度和铝铁摩尔比条件对乙烯聚合活性、所得双峰聚乙烯相对分子质量（M）及其分布（MWD）等的影响,发现该铁系催化剂在烷基铝的作用下,不但具有较高的乙烯聚合活性,而且所得聚乙烯相对分子质量分布始终保持双峰分布.并且采用原位紫外吸收光谱分析方法对该催化体系所产生的活性中心进行了表征,对双峰聚乙烯的形成机理进行了初步探讨,提出了2种活性中心的可能结构,认为该催化体系所得双峰聚乙烯的高分子量部分和低分子量部分分别由两种相互关联但又结构不同的活性中心所产生.The iron complex LFeCl 2（1）（L = 2,6-bis[（2,4,6-trimethylphenylimino） ethyl]pyridine） / triethylaluminum（TEA） catalyzed ethylene polymerization under different conditions.Bimodal polyethylene（PE）,which had different molecular weights and molecular weight distributions（MWD）,was prepared under various polymerization temperatures and the molar ratios of Al / Fe.The catalytic system had high activity of the ethylene polymerization and the produced polyethylene always had special molecular structure with the molecular weight distribution of two peaks by the GPC.Then the catalytic system was characterized through the in situ UV-Vis absorption spectra.A new applicable mechanism was proposed with the combination of the UVVis and the GPC results.There were two different kinds of catalytic species in the catalytic system at the same time.The distinctive behaviors of the catalytic system could result from the two different kinds of catalytic species that formed the bimodal PE.The two kinds of catalytic species had different structures and had some relationship.One kind of catalytic species produced the large molecular weight section of the bimodal PE,the other kind of catalytic species produced the small molecular weight section of the bimodal PE.The two kinds of catalytic species could transform each other under different conditions,which would benefit the production of the PE with different chain structures.

关 键 词：催化剂 铁 聚合 聚乙烯（PE） 

分 类 号：O643.36[理学—物理化学]