新型α-二亚胺合镍催化剂单一乙烯单体合成支化聚乙烯  

Novel (α-Diimine)nickel Catalyst for Preparing Branched Polyethylene with Single Ethylene Monomer

作　　者：祝方明[1] 徐卫[1] 刘新星[1] 林尚安[1] 

机构地区：[1]中山大学化学与化学工程学院,广东广州510275

出　　处：《中山大学学报（自然科学版）》2002年第2期40-43,共4页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家自然科学基金资助项目 (2 990 40 10 );广东省自然科学基金资助项目 (990 2 70 )

摘　　要：用新型α_二亚胺合镍氯化物 [2 ,6_(CH3 ) 2 C6H3 _N =C(CH3 )C(CH3 ) =N_2 ,6_(CH3 ) 2 C6H3 ]NiCl2 和甲基铝氧烷 (MAO)组成的催化剂进行乙烯均聚合 ,催化活性高达 7 3× 10 5g·mol- 1 ·h- 1 ,并且可以合成含有大量长支链的支化聚乙烯。研究了聚合温度和n(AlMAO) n(Ni)对催化活性以及聚乙烯相对分子质量、支化度和支链长度的影响。聚合物的支化度随聚合温度的升高而迅速增加 ,得到具有不同结晶度及无定型的支化聚乙烯。外加适量三异丁基铝 (TIBA)有助于提高催化剂活性 。Branched polyethylene containing primarily methyl and long branches was synthesized with a novel (α-diimine)nickel (Ⅱ) complex of 2,3-bis(2,6-dimethylphenyl)-butanediimine nickel dichloride { (CH 3) 2C 6H 3 N C(CH 3)C(CH 3) N 2,6-(CH 3) 2C 6H 3]NiCl 2}NiCl 2}(1) activated by methylaluminoxane (MAO) via ethylene homopolymerization. The influences of varying polymerization temperature and Al/Ni molar ratio on catalytic activity, as well as molecular weight, degree of branchingand branch length of polyethylene were investigated. The results of GPC characterization,indicate that the resultant polymers have weight average molecular weight ranged from 1.7×10 5 to 6.0×10 5 and rather narrow molecular weight distributions, showing the characteristic of ethylene polymerization catalyzed by single active species. The degree ofbranching rapidly increased with increasing polymerization temperature, giving rise to polymers ranging from highly crystalline to amorphous. The addition of triiosbutylaluminum (TIBA) to 1/MAO system could reduce the amount of MAO and leaded to significant enhancement of polymerization activity, while the polymer microstructure and molecular weight was slightly changed.

关 键 词：后过渡金属催化剂 α-二亚胺合镍配合物 支化聚乙烯 甲基铝氧烷 合成 聚合温度 支化度 

分 类 号：O632.12[理学—高分子化学] O643.36[理学—化学]