A Novel Laboratory Slurry Reactor for Ethylene Polymerization Studies

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• 作者：Jacek A. Szymura ; Ivo G. Dalla Lana ; Ryszard Fiedorow ; and Piotr A. Zielinski
• 刊名：Macromolecules
• 出版年：1996
• 出版时间：April 22, 1996
• 年：1996
• 卷：29
• 期：9
• 页码：3103 - 3110
• 全文大小：164K
• 年卷期：v.29,no.9(April 22, 1996)
• ISSN：1520-5835

文摘

A novel laboratory slurry reactor useful for studies ofpolymerization of olefins with solidcatalysts such as Cr/silica is described. The operation of thisreactor, in which gaseous impurities areminimized by purification of incoming gases and by in situactivation of the catalyst, has enabled theearly stages of the homopolymerization of ethylene to be studiedwithout interference from catalystdeactivation effects. By standardizing the conditions for theexperimental runs, the reactor demonstratedits usefulness in isolating and assessing the relative physical rolesof different silica supports. Fourcatalysts supported on different silica supports were compared, andtheir differences in promoting thepolymerization were interpreted in terms of porosity, average particlesize, and changes in specific surfacearea. During early polymerization, the fracturing of catalystsprepared by impregnation of the poroussilica support ensures access to these original Cr sites, in theabsence of additional concealed sites. Atlow yields, the polymerization process is clearly affected by thephysical character of the silica support;however, at higher yields, the evidence suggests that other causes suchas chemical effects are responsiblefor the continuing acceleration in rate. The porous Cr/silicacatalyst tested did not fracture instantaneously; hence, current models of nascent polymer do not describe thisprocess. The "hardcore" model ofnascent polymer seems applicable to polymerization on the nonporousCr/Cab-O-Sil catalyst tested.