Bimodal/Broad Polyethylene Prepared in a Disentangled State

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• 作者：Wei Li ; Chao Guan ; Jie Xu ; Zhong-ren Chen ; Binbo Jiang ; Jingdai Wang ; Yongrong Yang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：January 22, 2014
• 年：2014
• 卷：53
• 期：3
• 页码：1088-1096
• 全文大小：434K
• ISSN：1520-5045

文摘

Disentangled broad/bimodal polyethylene with an inverted distribution of short chain branches (SCBs) was synthesized with a supported hybrid catalyst. Poly[styrene-co-(acrylic acid)]- (PSA-) coated SiO₂ particles were used to support the hybrid catalysts. The PSA was coated on SiO₂-supported VCl₃ catalyst. Then, Fe(acac)₃/2,6-bis[1-(2-isopropylanilinoethyl)]pyridine was immobilized onto the PSA layer. It was demonstrated that the Fe(acac)₃/2,6-bis[1-(2-isopropylanilinoethyl)]pyridine catalyst prepared linear polyethylene with a low molecular weight (MW) and C4鈥揅22 伪-olefin. Meanwhile, this 伪-olefin could be used as the comonomer for VCl₃ to prepare high-MW polyethylene with SCBs. Hence, broad-MW-distribution polyethylene (MWD = 120) with an inverted distribution of SCBs was obtained from only one monomer (ethylene). Interestingly, this is the first time that the synthesized polyethylene was reported to exhibit a disentangled state. The isothermal kinetics of crystallization based on the Avrami and Tobin methods was studied to obtain details about the evolution of the disentangled state during the polymerization process.