Synthesis of Low Isotactic Polypropylene Using MgCl2/AlCl3-supported Ziegler–Natta Catalysts Prepared Using the One-Pot Milling Method

In this article, polymerization of 1-hexene with FeCl 3-doped Mg(OET) 2 /TiCl 4 /electron donor (ED) catalytic system is presented. For this purpose, first a number of TiCl 4 catalysts supported on Mg(OEt) 2 and Fe-doped Mg(OEt) 2 supports were prepared with ethylbenzoate or dibutylphthalate as the internal EDs. After successive catalysts synthesis, they were employed in 1-hexene polymerization using cyclohexyl methyl dimethoxysilane as external ED as well as without it. The catalysts activity and molecular weight distribution (MWD) of poly 1-hexenes (PHs) were influenced strongly by both FeCl 3 doping and donor presence so that a remarkable increase in the catalyst activity was seen in doped catalysts. Deconvolution of MWD curves revealed that increase in the type of active centers by introducing FeCl 3 into the support should be responsible for the broadening of MWD of PHs. 13 CNMR analysis indicated that while isotacticity does not change considerably by Fe doping, EDs increase its amount as high as 8-21%. Second, the stereoselective behavior of active Ti species in doped and undoped catalysts was fully explored by molecular modeling using density functional theory (DFT) method. Finally, with the aid of rheological measurements, the processability of polymers were evaluated and then the gel permeation chromatography (GPC) results were approved through the values obtained from model fitting as well as changes in moduli crossover modulus.

Section: Introductionmentioning

confidence: 99%

Synthesis of highly isotactic poly 1-hexene using Fe-doped Mg(OEt)₂/TiCl₄/ED Ziegler–Natta catalytic system

Nouri-Ahangarani

Bahri‐Laleh

Nekoomanesh‐Haghighi

et al. 2016

“…[15][16][17][18] Lately, investigations have shown that doping a suitable amount of Lewis acids in MgCl 2 or Mg(OEt) 2 supports would be an effective way to improve their catalytic performance in α-olefin polymerization. The mostly used doping agents were based on different metal halides such as MnCl 2 , [2] ZnCl 2 , [3] NaCl, [4] AlCl 3 [5,6,19], and the mixture of metal halide with metalloids like ZnCl 2 -SiCl 4 system. [7,8] These agents not only can have notable effect on catalyst activity but also have the ability to change catalyst efficiency toward higher α-olefins in LLDPE production as well as stereo-regularity of final polymer in propylene polymerization.…”

Section: Introductionmentioning

confidence: 99%

Highly efficient FeCl₃ doped Mg(OEt)₂/TiCl₄-based Ziegler–Natta catalysts for ethylene polymerization

Bazvand

Bahri‐Laleh

Nekoomanesh

et al. 2015

Seven Mg(OEt) 2 /FeCl 3 /SiCl 4 /TiCl 4 type procatalysts supported on Mg(OEt) 2 /FeCl 3 mixtures were prepared in order to unravel effect of Fe doping on the catalytic performance in ethylene polymerization. In polymerization experiments, the catalyst based on a support containing an optimum doping amount of 10 wt.% of FeCl 3 , i.e. C-F 10 -Si, exhibited an activity 2.4 times greater than that shown by the reference catalyst, C-M. The MW and bulk density of the produced polymers were increased, while the wax amount decreased using doped catalysts. In the next step, the copolymerization of ethylene with 1-hexene was carried out using C-M as reference and C-Fe 10 -Si as the most efficient procatalysts. In copolymerization experiments, C-Fe 10 -Si exhibited much higher activity and comonomer incorporation in comparison with reference catalyst. Finally, to shed light on possible interaction of TiCl 4 with doped and undoped catalysts, as well as their efficiency in ethylene polymerization, molecular simulation was performed. Energy results revealed that the doping does not alter significantly the capability of the Ti to insert ethylene monomer.

“…Polypropylene (PP) is one of the most widely used plastics due to its excellent chemical and physical properties[1–4]. However, since PP is a nonpolar polymer, its colorability, adhesiveness and compatibility with polar materials are comparatively poor, which seriously hindered its application[5,6].…”

Section: Introductionmentioning

confidence: 99%

Study of suspension grafting process of polypropylene

Liang

Yuan

Shao

et al. 2018

Grafting efficiency is an important indicator of polypropylene grafting reaction. A series of studies have been accomplished, including the conditions of free radical presence on PP backbone during peroxide initiation, the effect of preheat treatment and reaction time on PP suspension grafting results, and the effect of peroxide residue on properties of modified PP. An optimized grafting process was proposed by mixing and preheating polypropylene (PP) and the initiator benzoyl peroxide (BPO) before adding the grafting monomer glycidyl methacrylate (GMA),resulting in an increase in grafting efficiency from 50.0% to 78.2%. With initiator residue removed by alternating temperature treatment, the suspension grafting reaction time could be substantially reduced.