Ethene was copolymerized with 1-octene using homogeneous MAO-activated rac-Me 2 Si(2-MeBenz[e]Ind) 2 ZrCl 2 at constant ethene concentration with temperature varying between 0 and 60ΠC to determine a temperature dependence of copolymerization parameters. At constant 1-octene and ethene concentration
Copolymerization of propylene with 1-octene catalyzed by rac-Me2Si(2,4,6-Me3-Ind)2ZrCl2/methyl aluminoxane
β Scribed by Zhi-Qiang Fan; Tariq Yasin; Lin-Xian Feng
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 167 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0887-624X
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β¦ Synopsis
The copolymerization of propylene with 1-octene was carried out with rac-dimethylsilylbis (2,4,6-trimethylindenyl)zirconium dichloride as a catalyst activated by methylaluminoxane (MAO) and an MAO/triisobutylaluminum mixture. The copolymerization conditions, including the polymerization temperature, Al/Zr molar ratio, and 1-octene concentration in the feed, significantly influenced the catalyst activity, 1-octene incorporation, polymer molecular weight, and melting temperature. The addition of 1-octene to the polymerization system caused a decrease in the activity, whereas the melting temperature and intrinsic viscosity of the polymer increased. The microstructure of the propylene-1-octene copolymer was characterized by 13 C NMR, and the reactivity ratios of the copolymerization were estimated from the dyad distribution of the monomer sequences. The amount of regioirregular structures arising from 2,1-and 1,3-misinserted propylene decreased as the 1-octene content increased. The influence of the propagation chain on the polymerization mechanism is proposed to be the main reason for the changes in the reactivity ratios and regioirregularity with the polymerization conditions.
π SIMILAR VOLUMES
The main focus of this study is the ethylene/hexene copolymerization with the silica supported metallocene SiO 2 /MAO/rac-Me 2 Si[2-Me-4-Ph-Ind] 2 ZrCl 2 . Polymerizations were carried out in toluene at a reaction temperature of 40 8C-608C and the cocatalyst used was triisobutylaluminium (TIBA). The
DSC heating traces of the propene homopolymer and the propene/OD copolymers.
Ansa-zirconocene diamide complex rac-Me 2 Si(CMB) 2 Zr(NMe 2 ) 2 (rac-1, CMB Ο 1-C 5 H 2 -2-Me-4-t Bu) reacts with AlR 3 (R Ο Me, Et, i-Bu) and then with [CPh 3 ] Ο© [B(C 6 F 5 ) 4 ] Οͺ (2) in toluene in order to in situ generate cationic alkylzirconium species. In the sequential NMR-scale reactions o
The kinetics of propylene polymerization initiated by ansa-metallocene diamide compound rac-Me 2 Si(CMB) 2 Zr(NMe 2 ) 2 (rac-1, CMB Ο 1-C 5 H 2 -2-Me-4-t Bu)/ methylaluminoxane (MAO) catalyst were investigated. The formation of cationic active species has been studied by the sequential NMR-scale rea
The kinetics of ethene and propene polymerization at 20 -60 8C in the presence of the homogeneous catalyst system rac-Me 2 Si(2-methyl-4-phenyl-1-indenyl) 2 ZrCl 2 /methylaluminoxane was investigated by means of stopped-flow techniques. The specific rate of chain propagation, measured at the very sh