نتایج جستجو برای: natta catalysts

تعداد نتایج: 33137  

Journal: :Chemcatchem 2022

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...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
omid vahidi mohammad shahrokhi ahmad mirzaei

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - پژوهشکده علوم 1388

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...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2006
Cristiane F Petry Larissa B Capeletti Fernanda C Stedile João H Z Dos Santos Dirce Pozebon

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...

Journal: :Journal of Polymer Research 2021

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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