一种新型亚胺基吡啶铁配合物和茂金属复配催化乙烯原位共聚制备LLDPE

Linear low density polyethylene from ethylene as an o nly monomer was prepared by the combination catalyst system of Et(Ind) 2ZrCl 2 an d {2 [2 Me 4 Br C 6H 3NC(Me)] 2C 5H 3N}FeCl 2 activated with methy laluminoxane (MAO).The two catalysts were well matched in a single reactor and i t was observed that the “comonomer effect" appeared in the in situ copolymeriz ation of ethylene.The comonomer effect was some strongly influenced by the molar ratio of Al to (Fe+Zr) and the polymerization temperatures.At 60℃ and n(Al )/n(Fe+Zr)=2000,the maximum activity of the catalytic system(8 5×10\+6g/mo l·h) was 4\^25 times higher than that of homopolymerization of ethylene(2\^0×1 0\+6g/mol·h),and the value of n(Fe)/n(Zr) was 0 5.At n(Al)/n(F e+Zr)=1000,the maximum activity diminished.When polymerization temperatures incr eased,the maximum activity of the in situ copolymerization decreased and the co rresponding ratio of Fe to Zr also decayed.The copolymers made from this catalyt ic system had the characteristics of low melting point(from 132 34℃ to 70 97 ℃),low density(from 0 9467?g/cm\+3 to 0\^9283?g/cm\+3) and narrow molecular weight distribution(from 2\^29 to 1\^86).However,it’s no obvious influence of th e comonomer effect on the physical properties of the copolymers.

铁系亚胺基吡啶复配催化乙烯原位共聚产物的表征

Branched polyethylene from ethylene as single monomer was prepared by the tandem catalyst system of {2-[2-Me C6H4 N（Me）]2C5H3N}FeCl2（1） and {2,6-[1-(2,6-Me2-4-Br-C6H4N（Me）]2C5H3N} FeCl2（2） activated with methylaluminoxane （MAO） .The products of polymerization were characterized by DSC,GPC and （）13C-NMR.The results revealed that the copolymer produced by in situ copolymerization of ethylene was a mixture of branched polyethylene and α-olefin.The content of α-olefin in the mixture was increased with increasing the molar ratio of catalysts 1/2.The MWD paramelers of polyethylene and copolymer were 28\^6 and 7\^9, respectively.（）13C-NMR spectra showed that there were ethyl groups,butyl groups and long chain alkyl groups in the copolymer.The average degree of branching of such branched polyethylene was less than 5C/1000C.

亚胺基吡啶铁配合物/茂金属催化乙烯原位共聚中的共单体效应

研究了亚胺基吡啶铁配合物{[(2-Me-4-R-C6H4N=C(Me))2C5H3N]FeCl2}(1R=Br,2R=OMe)分别与茂金属Et[Ind]2ZrCl2复配催化乙烯原位共聚中的共单体效应。探讨了齐聚催化剂的活性和聚合反应温度对共单体效应的影响,以及共单体效应对所得产物物理性能的影响。结果表明,随着齐聚催化剂活性的降低,出现共单体效应时两种主催化剂的最佳配比值增加;聚合温度的升高使最高活性值下降。共单体效应对所得共聚物的物理性能影响不明显。

后过渡金属铁系催化剂与Et[Ind]_2ZrCl_2复配催化乙烯原位共聚中的“共单体效应”

研究了以{2-[2-MeC6H4N=C(Me)]2C5H3N}FeCl2为齐聚催化剂、以Et[Ind]2ZrCl2为共聚催化剂复配,在甲基铝氧烷作用下催化乙烯原位共聚的“共单体效应”。在n(Al)/n(Zr)、n(Al)/n(Fe)和n(Al)/n(Fe+Zr)分别为2000时,改变齐聚催化剂/共聚催化剂的配比,均观察到共单体效应。探讨了助催化剂用量、主催化剂用量和聚合温度对共单体效应的影响。助催化剂用量的增加使出现最佳活性点的n(Fe)/n(Zr)发生了前移,而主催化剂用量的增加使出现最佳活性点的n(Fe)/n(Zr)发生了后移。聚合温度的改变使共单体效应的变化规律发生了改变。