a fourth-generation ziegler-natta catalyst was prepared to synthesize polypropylene (pp), which was stabilized by in situ polymerization employing lignin as antioxidant. the antioxidant properties of lignin were compared with those of the commercial antioxidant irganox 1010. the presence of lignin in the reaction medium slightly decreased the catalytic activity of the reaction. the isotacticity...

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 different...

Mg(OEt)2 with spherical morphology is one of the most important precursors for the preparation of industrial Ziegler-Natta catalysts. In the present article, morphology evolution of Mg(OEt)2 particles is studied in the course of the synthesis. The morphology of Mg(OEt)2 particles is observed throughout the process by SEM. The results show that Mg(OEt)2 particles are formed through i) seed gener...

We have been engaged in a search for coordination catalysts for the copolymerization of polar monomers (such as vinyl chloride and vinyl acetate) with ethylene. We have been investigating complexes of late transition metals with heterocyclic ligands. In this report we describe the synthesis of a symmetrical bis-thiadiazole. We have characterized one of the intermediates using single crystal X-r...

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...