β-二酮锆／AlEt2Cl／MAO催化乙烯原位共聚合成支化聚乙烯  

Synthesis of Branched Polyethylene from Ethylene via in situ Copolymerization Catalyzed by β-Diketonate Zirconium/AlEt_2Cl/MAO

作　　者：胡文艳[1] 杨敏[1] 赵辛[2] 刘宾元[1] 郝小宇[1] 闫卫东[1] 

机构地区：[1]河北工业大学化工学院高分子科学与工程研究所,天津300130 [2]中国人民解放军95989部队,北京100076

出　　处：《高等学校化学学报》2008年第2期430-432,共3页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:50573018)资助

摘　　要：A novel catalytic system to prepare branched polyethylene with single catalyst activated by two different co-catalysts is reported in this paper via the tandem catalysis,with ethylene as single monomer.Such catalytic system is composed of β-diketonate zirconium complexes,i.e.(acac)2ZrCl2(Ⅰ)and(dbm)2ZrCl2(Ⅱ)as catalyst precursors,diethylaluminium chloride(AlEt2Cl)as a co-catalyst for ethylene oligomerization and methylaluminoxane(MAO)as another one for the in situ copolymerization with ethylene.The oligomers obtained were mainly α-olefins,and the contents of them in weight were 76.84 for Ⅰ and 65.99 for Ⅱ,while the part being able to be copolymerized was 62.12 and 55.32 for Ⅰ and Ⅱ,respectively.The branched polyethylene via in situ copolymerization of ethylene was prepared by the tandem catalytic system Ⅰ/AlEt2Cl/MAO or Ⅱ/AlEt2Cl/MAO.13C NMR spectrum reveals that the resultant copolymer was branched polyethylene with total branches of 2.1/1000C,including ethyl group of 1.2/1000C,butyl group of 0.8/1000C and longer branches of 0.1/1000C.With increasing the molar ratio of AlEt2Cl to MAO,the melting temperature of the polymer obtained decreased from 133.7 to 116.7 ℃ for Ⅰ/AlEt2Cl/MAO and from 131.7 to 118.8 ℃ for Ⅱ/AlEt2Cl/MAO as well as the change of crystallinity.The catalytic activities for catalyst Ⅰ/AlEt2Cl/MAO and Ⅱ/AlEt2Cl/MAO were from 2.48×104 to 0.10×104 g PE/(mol Zr·h)and from 1.00×104 to 0.32×104 g PE/(mol Zr·h),respectively.The results indicate that the branched polyethylene can be obtained by such a catalytic system.A novel catalytic system to prepare branched polyethylene with single catalyst activated by two different co-catalysts is reported in this paper via the tandem catalysis, with ethylene as single monomer. Such catalytic system is composed of β-diketonate zirconium complexes, i.e. （acac）2ZrCl2（ Ⅰ ） and （dbm）2ZrCl2 （ Ⅱ ） as catalyst precursors, diethylaluminium chloride（AlEt2Cl） as a co-catalyst for ethylene oligomerization and methylaluminoxane（MAO） as another one for the in situ copolymerization with ethylene. The oligomers obtained were mainly α-olefins, and the contents of them in weight were 76. 84% for Ⅰ and 65.99% for Ⅱ , while the part being able to be copolymerized was 62. 12% and 55.32% for Ⅰ and Ⅱ , respectively. The branched polyethylene via in situ copolymerization of ethylene was prepared by the tandem catalytic system Ⅰ/AlEt2CL/MAO or Ⅱ/AlEt2CL/MAO. ^13C NMR spectrum reveals that the resultant copolymer was branched polyethylene with total branches of 2. 1/1000C, including ethyl group of 1.2/1000C, butyl group of 0. 8/ 1000C and longer branches of 0. 1/1000C. With increasing the molar ratio of AlEt2C1 to MAO, the melting temperature of the polymer obtained decreased from 133.7 to 116. 7 ℃ for Ⅰ/AlEt2CL/MAO and from 131.7 to 118.8 ℃ for Ⅱ/AlEt2Cl/MAO as well as the change of crystallinity. The catalytic activities for catalyst Ⅰ/AlEt2C1/MAO and Ⅱ/AlEt2Cl/MAO were from 2. 48 × 10^4 to 0. 10 × 10^4 g PE/（mol Zr · h） and from 1.00 × 10^4 to 0. 32× 10^4 g PE/（mol Zr · h）, respectively. The results indicate that the branched polyethylene can be obtained by such a catalytic system.

关 键 词：乙烯原位共聚 支化聚乙烯 β-二酮锆配合物 一氯二乙基铝 甲基铝氧烷 

分 类 号：O631[理学—高分子化学]