Novel MgCl2-supported catalyst containing diol dibenzoate donor for propylene polymerization

Control of molecular weight distribution for polypropylene obtained by commercial ziegler-natta catalyst: Effect of electron donor

“…The effect of external donor on propylene polymerization was reported by many researchers. [3][4][5][6][12][13][14]17,18 According to the previous section, the molecular weight was affected by the structure of external donor. In order to produce PP with broad molecular weight distribution, the polymerization was carried out with Cat-B and the mixture of external donors.…”

“…4,11 The resulting catalyst system was chemical complexity and the resulting PP present very different properties depending on the synthetic conditions. [4][5][6][7] The nature of the added external donor can strongly modify the tacticity of the resulting polymers, which can range from atactic PP to extremely isotactic PP, the molecular weight distribution, which can be rather narrow or rather broad. 8 Alkoxysilanes were cited as external donors in the large number of research for Ziegler-Natta catalyst systems.…”

“…14 External donors markedly increase the stereospecificity of PP and usually decrease the activity of Ziegler-Natta catalysts. [3][4][5][6]12,14 Some studies on the influence of external alkoxysilane donor on molecular weight distribution have been reported. 3,12-14 Soga et al 3 reported that the gel permeation chromatography (GPC) curve tend to shift towards higher molecular weight region by addition of triethoxyphenylsilane as an external donor.…”

The effect of mixed and individual silane external donors on the stereo-defect distribution, active sites and properties of polypropylene synthesized with fourth generation Ziegler—Natta catalyst

“…Currently, it is mostly synthesized in industry using fourth generation Ziegler-Natta catalyst, which is comprised of MgCl 2 -supported TiCl 4 catalyst and a diester such as diisobutyl phthalate as internal donor [3][4][5]. Heterogeneous Ziegler-Natta catalysts con tain multiple active sites that have specific properties like stereo regularity, transfer and propagation rate constants.…”

Investigation of the effect of branched structure on the performances of the copolymers synthesized from ethylene and α-olefin with rac-Et(Ind)2ZrCl2/MMAO catalyst system

“…The development of catalysts technology has lead to the synthesis of a rich set of new polymers with different structures and performances to feed up the progressive demand of modern industry and life [1][2][3][4][5][6][7][8][9][10][11][12]. Recently, the branched polyethylenes such as linear low-density polyethylene (LLDPE) have grown in importance because of the specific properties that can be obtained by varying comonomer content and polymerization condition.…”