With different structure ligands heterogeneous Ziegler–Natta catalysts for the preparation of copolymer of ethylene and 1-octene with high comonomer incorporation
✍ Scribed by Yuan Kong; Jianjun Yi; Xiuli Dou; Weijiao Liu; Qigu Huang; Kejing Gao; Wantai Yang
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 476 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
Comparison with the conventional ZieglereNatta catalyst TiCl 4 /MgCl 2 (I), the modified supported Zie-glereNatta catalysts (iso-PentylO)TiCl 3 /MgCl 2 (II) and (BzO)TiCl 3 /MgCl 2 (III) were prepared as efficient catalysts for copolymerization of ethylene with 1-octene. The complexes (II) and (III) were desirable for the production of random ethylene/1-octene copolymers coupled with higher molecular weight, higher comonomer incorporation within copolymer chain and good yield even at high temperature 80 C and fairly low Al/Ti molar ratio of 100. The effects of catalysts ligands, Al/Ti molar ratio, polymerization temperature, as well as concentration of 1-octene on the catalytic activity, molecular weight and microstructure of the copolymer were investigated in detail. The structure and properties of the copolymers were characterized with 13 C NMR, GPC, DSC and WAXD. The kinetic results also indicate that these catalysts (II) and (III) show higher catalytic activity and the produced polymers feature higher molecular weight, because of lower ratio of K trm /K p and K tra /K p , and higher ratio of K tra /K trm which indicates that chain transfer to cocatalyst is predominant.