Preparation of linear low-density polyethylene by the In situ copolymerization of ethylene with an iron oligomerization catalyst and rac-ethylene bis(indenyl) zirconium (IV) dichloride
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发布时间：2025-04-30
发布时间：2025-04-30
论文名称：Preparation of linear low-density polyethylene by the In situ copolymerization of ethylene with an iron oligomerization catalyst and rac-ethylene bis(indenyl) zirconium (IV) dichloride
发表刊物：Journal of Polymer Science A: Polymer Chemistry
摘要：An iron oligomerization catalyst, [(2-ArN C(Me))(2)C5H3N]FeCl2 [Ar = 2,6-C6H3(F)(2)], was combined with rac-ethylene bis(indenyl)zirconium (IV) dichloride [rac-Et(Ind)(2)ZrCl2] to prepare linear low-density polyethylene (LLDPE) by the in situ copolymerization of ethylene. A series of LLDPEs with different properties were prepared by the alteration of the reaction temperature, Fe/Zr molar ratio, Al/(Fe + Zr) molar ratio, and reaction time. The structures of the polymers were characterized with differential scanning calorimetry, C-13 NMR, gel permeation chromatography (GPC), and so forth. The melting points, crystallizations, and densities of the resulting products increased, and the average branching degree decreased, as the reaction temperature, Al/(Fe + Zr) ratio, and reaction time increased. The melting points, crystallizations, and densities of the polymers decreased, and the average branching degree increased, when the Fe/Zr ratio increased. The C-13 NMR and GPC results showed that there were no unreacted alpha-olefins remaining in the resulting polymers because the percentage of low-molar-mass sections (C-4-C-10) of the oligomers obtained with this catalyst was very high (>70%). In addition, the formation of polymers with two melting points under different reaction conditions was examined in detail, and the results indicated that the two melting points of the polymers could be attributed to polyethylene with different branches.
合写作者：Zhicheng Zhang; Nannan Cui; Youliang Hu
卷号：Volume: 43 Issue: 5
页面范围：984-993
是否译文：否
发表时间：2005-03-01