Effects of Some New Alkoxysilane External Donors on Propylene Polymerization in MgCl2-Supported Ziegler鈥揘atta Catalysis

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• 作者：Qian Zhou ; Tao Zheng ; Huayi Li ; Qian Li ; Yu Zhang ; Liaoyun Zhang ; Youliang Hu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：November 19, 2014
• 年：2014
• 卷：53
• 期：46
• 页码：17929-17936
• 全文大小：280K
• ISSN：1520-5045

文摘

Five new alkoxysilanes with different sizes of hydrocarbon substituents were first synthesized and employed as external donors for propylene polymerization with a Ziegler鈥揘atta catalyst. The effects of these and industrial alkoxysilanes with different sizes of hydrocarbon substituents on the microstructure of polypropylene were studied by SSA and ¹³C NMR. The results showed that isotactic sequence length of polypropylene increased with the size of R₂ substituent on alkoxysilanes in the five donor systems, similar to the regularity of molecular weight, isotacticity, and thermal properties of polypropylene. Although the polypropylene produced by double cycloalkane substituents on alkoxysilanes had lower lamellae thickness L₁, its contents were the highest. Moreover, excess large volume of hydrocarbon substituents on alkoxysilanes might be detrimental to improving isotactic sequence length of polypropylene. Polypropylene prepared by MIPDMS had a more uniform distribution of the stereodefects, indicating that MIPDMS might be used for the industrial production of BOPP.