Microstructure of ethylene-1-hexene and ethylene-1-octene copolymers obtained over Ziegler–Natta catalysts supported on MgCl 2 (THF) 2

Czaja, Krystyna; Białek, Marzena

doi:10.1016/s0032-3861(00)00621-2

Cited by 49 publications

(37 citation statements)

References 28 publications

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“…Catalysts for isospecific propylene polymerization usually contain diester compounds such as ID [5]. MgCl 2 ·nTHF adducts are often used to prepare supported catalysts suitable for ethylene-α-olefin copolymerization [17,18]. This kind of catalysts actually contains THF as ID.…”

Section: Introductionmentioning

confidence: 99%

Dependence of comonomer effect and hydrogen effect on internal donor in ethylene/1-hexene copolymerizations with MgCl2-supported catalysts

Zhang

Fan

et al. 2010

E-Polymers

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Abstract:Ethylene homopolymerization and copolymerizations with 1-hexene by three types of MgCl 2 -supported catalysts were compared. Cat-1 contains no internal electron donor (ID), Cat-2 contains phthalic anhydride (PA) as ID, and Cat-3 contains anisole as ID. The influences of two kinds of ID on comonomer effect, the role of hydrogen, polymerization kinetics in ethylene/1-hexene copolymerization were investigated. The addition of ID improves the catalysts activities in ethylene polymerization. In comparison with ethylene homopolymerization, these ethylene/1-hexene copolymerization systems all showed strong comonomer effects. However, internal donor, especially anisole, weakens the extent of comonomer activity enhancement. When the concentration of 1-hexene is 0.6 mol/L, catalysts activities increase remarkably with adding a small amount of hydrogen. But, the addition of ID reduces the sensitivity of catalyst activity to hydrogen. The introduction of anisole increases the homo-polymerization rate rapidly at the initial stage, but makes it decay earlier. In ethylene/1-hexene copolymerization with hydrogen, the addition of phthalic anhydride as ID can stabilize the polymerization rate, but anisole accelerates the decaying trends. The results are discussed based on a kinetic mechanistic model of the ID effect on ethylene copolymerization.

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Section: Introductionmentioning

confidence: 99%

Dependence of comonomer effect and hydrogen effect on internal donor in ethylene/1-hexene copolymerizations with MgCl2-supported catalysts

Zhang

Fan

et al. 2010

E-Polymers

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“…The literature contains findings that indicate the insertion of alpha-olefins in the polymeric matrix influences the crystallinity of samples, modifying the thermal properties [29][30][31] . In this way, it is possible to suggest that the presence of alpha-olefin in the polybutadiene chain creates crystalline segments, generated by the packing of the branches, resulting in the increase of the materials' thermal stability.…”

Section: Influence Of Alpha-olefin Addition On Thermal Stabilitymentioning

confidence: 99%

Copolymerization of 1-hexene and 1-dodecene with 1,3-butadiene by a versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system

et al. 2014

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Abstract:The aim of this study was to incorporate an alpha-olefin (1-hexene or 1-dodecene) in a high cis polybutadiene chain, using a neodymium versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system. The influence of alpha-olefin on polymerization reaction and polymer characteristics, using different weight ratios of butadiene/α-olefin, was evaluated. The copolymers were characterized by SEC, FTIR, NMR, TGA and viscosimetric analysis. The thermal stability of the polymer tended to increase with incorporation of alpha-olefins, while its microstructure was not affected. The weight average molecular mass (Mw) tended to increase and the polymerization conversion tended to decrease with increasing alpha-olefins content. The copolymers showed a lower intrinsic viscosity than for the homopolymer. The results indicated that the alpha-olefins were incorporated in the polybutadiene chain.

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“…More than twenty million tons of LLDPE resin is now produced every year in the world. Because of its great importance, many literatures have been published in the studies of ethylene-α-olefin copolymerization catalyzed by supported Ziegler-Natta catalysts and metallocene catalysts [1][2][3][4][5][6][7][8][9][10][11]. Ziegler-Natta catalysts produced ethylene-α-olefin copolymer with broad chemical composition distribution (CCD) resulted from the presence of multiple active sites on the heterogeneous catalysts, and enrichment of α-olefin in the fraction with low molecular mass.…”

Section: Introductionmentioning

confidence: 99%

“…They are usually prepared by contacting anhydrous magnesium chloride or its compounds with titanium tetrachloride. MgCl 2 ·nTHF adducts are often used to prepare supported catalysts suitable for ethylene-α-olefin copolymerization [1,2]. This kind of catalysts actually contains THF as ID.…”

Section: Introductionmentioning

confidence: 99%

Effect of internal electron donor on copolymerization of ethylene and 1-hexene catalyzed by supported Ziegler- Natta catalysts

Fan

Zhang

2008

E-Polymers

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Abstract:The four kinds of TiCl 4 /MgCl 2 type supported Ziegler-Natta catalysts, Cat-1, Cat-2, Cat-3 and Cat-4, were prepared by reaction of MgCl 2 -ethanol adduct with TiCl 4 . Cat-1 contains no internal electron donor (ID), Cat-2 contains diethyl phthalate (DEP) as ID, Cat-3 contains anisole as ID, and Cat-4 contains both DEP and anisole as ID. Ethylene copolymerizations with 1-hexene by these catalysts were compared. Influences of the internal electron donor on catalyst activity, copolymer composition, composition distribution, molecular weight and molecular weight distribution were investigated. Cat-3 showed the largest ability of incorporating 1-hexene into copolymer chains among the four catalysts. Each copolymer sample was fractionated into two fractions: fraction soluble in boiling nheptane (HS) and fraction insoluble in boiling n-heptane (HI). 1-Hexene content of the HS fraction is 6~10 times of that in the HI fractions. Amount of the HS fraction of copolymer by Cat-2 and Cat-4 was much lower than that of Cat-1 and Cat-3. Introduction of internal donor to the catalysts, especially diethyl phthalate (DEP), increased the blockiness of HI fractions. The molecular weight of both fractions increased when there is ID in the catalyst. Addition of anisole reduced the difference in molecular weight between HS fraction and HI fraction, but addition of PA enlarged the difference. The results are discussed based on a mechanistic model of MgCl 2 -supported Ziegler-Natta catalysts.

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Microstructure of ethylene-1-hexene and ethylene-1-octene copolymers obtained over Ziegler–Natta catalysts supported on MgCl 2 (THF) 2

Cited by 49 publications

References 28 publications

Dependence of comonomer effect and hydrogen effect on internal donor in ethylene/1-hexene copolymerizations with MgCl2-supported catalysts

Dependence of comonomer effect and hydrogen effect on internal donor in ethylene/1-hexene copolymerizations with MgCl2-supported catalysts

Copolymerization of 1-hexene and 1-dodecene with 1,3-butadiene by a versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system

Effect of internal electron donor on copolymerization of ethylene and 1-hexene catalyzed by supported Ziegler- Natta catalysts

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