نتایج جستجو برای: natta catalysts
تعداد نتایج: 33137 فیلتر نتایج به سال:
Strict morphological control over growing polymer particles is an indispensable requirement in many catalytic olefin polymerization processes. In catalysts with mechanically stronger supports, e. g., polymerization-grade silicas, the emergence of extensive cracks via sectioning fragmentation mechanism requires severe stress build-up polymerizing catalyst particle. Here, we report on three facto...
in present paper, dynamic behavior and control of a fluidized bed reactor for polyethylene production has been considered. a double active sites model for ziegler-natta catalysts is used for simulation of polymerization reaction. hydrodynamic behavior of the bed is modeled using a two phase model including bubble and emulsion phases in which bubble phase has plug flow pattern with differentiall...
heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...
A method for the determination of Ti and V using inductively coupled plasma atomic emission spectrometry (ICP OES) in Ziegler-Natta polymerization catalysts is proposed. The concentrations of both Ti and V are efficiently determined after catalyst acid digestion with a mixture of HNO3 + HCl + HF and heating (160 degrees C for 6 h) or with 10% (v/v) H2SO4 and heating (160 degrees C for 6 h) or w...
Abstract The scientific and technical advances in the field of polymer science has been abundant recent years. Amongst various polymeric materials available market, synthesis polyolefins forefront since decades. A major challenge this domain remains attaining stereoregular especially polypropylene (PP) significant efforts were carried out by synthesizing internal donors (ID) aiding catalysts in...
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