Isobutylalumoxanes as high-performance activators of rac-Et(2-MeInd)2ZrMe2 in copolymerization of ethylene with propylene and ternary copolymerization of ethylene, propylene, and 5-ethylidene-2-norbornene
Isobutylalumoxanes as high-performance activators of rac-Et(2-MeInd)2ZrMe2 in copolymerization of ethylene with propylene and ternary copolymerization of ethylene, propylene, and 5-ethylidene-2-norbornene
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DOI：
10.1007/s00289-015-1505-2
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发表时间：
2016-02-01
期刊：
影响因子：
3.2
通讯作者：
Perepelitsina, Eugenia O.
中科院分区：
文献类型：
--
作者：
Bravaya, Natalia M.;Panin, Andrei N.;Perepelitsina, Eugenia O.
三异丁基铝(TIBA)在Al-TIBA/H2O=2摩尔/摩尔的条件下，以水(1)或冰粒(2)的形式与水进行水解制得异丁基铝氧烷。H-1核磁共振谱表明，水解物中存在未反应的TiBA，表明生成了大于(Bu2Al)-Bu-I-O-Ali-Bu-2的氧化铝氧烷，这是根据试剂的摩尔比可以预期的。在乙烯与丙烯的共聚反应以及乙烯与丙烯和5-亚乙叉-2-降冰片烯的三元共聚反应中，铝氧烷1和2对RAc-Et(2-MeInd)(2)ZrMe2表现出较强的活化能力。铝氧烷1在长期储存(1年)中表现出很高的结构和化学稳定性，导致形成的聚合物具有一致的活化能力和相似的分子量特征。铝氧烷2的结构稳定性要差得多，这表现在产品的H-1核磁共振谱即使在储存几天后也有很大的变化。储存3个月后基本失去激活能力。在Al-TiBA/H2O=2摩尔/摩尔条件下，在聚合前用有意加入到甲苯中的水(类似于1×10~(-2)摩尔/L)原位TIBA水解也得到了活性较高的铝氧烷。不同活化剂催化体系的差异还体现在形成的共聚物的微观结构、相对分子质量、热物理特性和物理机械性能等方面的差异。
Isobutylalumoxanes have been obtained by hydrolysis of triisobutylaluminium (TIBA) with water in the form of vapour (1) or ice particles (2) at Al-TIBA/H2O = 2 mol/mol. H-1 NMR spectra of hydrolyzates showed the presence of unreacted TIBA indicating the formation of alumoxanes larger than (Bu2Al)-Bu-i-O-Ali- Bu-2 which one can expect based on the molar ratio of reagents. Alumoxanes 1 and 2 demonstrate high activating ability for rac-Et(2-MeInd)(2)ZrMe2 in copolymerization reactions of ethylene with propylene and terpolymerization of ethylene with propylene and 5-ethylidene-2-norbornene. Alumoxane 1 demonstrates high structural and chemical stability during long-term storage (for 1 year) that results in consistent activating ability and similarity of molecular weight characteristics of polymer formed. Alumoxane 2 is much less structurally stable which is manifested in considerable changes of H-1 NMR spectra of the product even after several days of storage. It essentially loses activating ability after 3 months' storage. The alumoxanes with high activating ability have been also obtained by in situ TIBA hydrolysis with water intentionally incorporated into toluene (similar to 1 x 10(-2) mol/l) prior to polymerization also at Al-TIBA/H2O = 2 mol/mol. The differences of catalytic systems with different activators are also reflected in differences in microstructure, molecular-weight, thermal-physical characteristics and physicalmechanical properties of copolymers formed.