Copolymerization of ethylene and propylene over the SiO2-supported MgCl2/TiCl3 catalyst

Soga, Kazuo; Ohnishi, Rikuo; Sano, Tsuneji

doi:10.1007/bf00256085

Cited by 30 publications

(7 citation statements)

References 5 publications

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“…The overall cies having relatively low activity with respect to monomer insertion. In recent studies with MgCl 2 / polymer yield, however, decreases by a factor 5, greater than that observed with the MgCl 2 /TiCl 4 TiCl 4 /phthalate ester-AlEt 3 -alkoxysilane systems, 11 with MgCl 2 /TiCl 4 /diether-AlEt 3 syscatalyst. The productivity of isotactic polymer is also significantly lowered by the presence of the tems 12 and with metallocene catalysts, 20,21 it has been demonstrated, via chain-end analysis of donor, both in the presence and absence of hydrogen.…”

Section: Introductioncontrasting

confidence: 49%

“…However, our EPR results The results are shown in Figure 1. Again, it is seen that the activity of the Ti-arene-based cata- 4 and TiCl 3 , respectively, evidenced the forthe internal donor is preferentially complexed on mation of a considerable amount of plurideuterthe (110) face, thus avoiding the formation on this ated methane probably resulting from deuteroplane of nonstereospecific sites. Therefore, the inlysis of carbon-bridged Al/Ti species.…”

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Propylene polymerization with catalysts containing divalent titanium

Albizzati¹,

Giannini²,

Balbontin³

et al. 1997

J. Polym. Sci. A Polym. Chem.

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Section: Introductioncontrasting

confidence: 49%

Section: Introductionmentioning

confidence: 95%

Propylene polymerization with catalysts containing divalent titanium

Albizzati¹,

Giannini²,

Balbontin³

et al. 1997

J. Polym. Sci. A Polym. Chem.

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“…The very broad fraction precipitating at lower temperatures, from ∼70 to 30 °C (∼35%), represents the branched material in Flory components III and II, whereas the fraction that remains in solution even at 30 °C (∼20%, not shown in the figure) is the highly branched material in Flory components I and partially II. The difference in the copolymerization abilities of different active centers was noticed a long time ago;9, 33, 34, 14 the above GPC and Crystaf results assign the differences to particular populations of active centers.…”

Section: Resultsmentioning

confidence: 79%

Multicenter nature of titanium‐based Ziegler–Natta catalysts: Comparison of ethylene and propylene polymerization reactions

Kissin

2003

J. Polym. Sci. A Polym. Chem.

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This article discusses the similarities and differences between active centers in propylene and ethylene polymerization reactions over the same Ti-based catalysts. These correlations were examined by comparing the polymerization kinetics of both monomers over two different Ti-based catalyst systems, ␦-TiCl 3 -AlEt 3 and TiCl 4 / DBP/MgCl 2 -AlEt 3 /PhSi(OEt) 3 , by comparing the molecular weight distributions of respective polymers, in consecutive ethylene/propylene and propylene/ethylene homopolymerization reactions, and by examining the IR spectra of "impact-resistant" polypropylene (a mixture of isotactic polypropylene and an ethylene/propylene copolymer). The results of these experiments indicated that Ti-based catalysts contain two families of active centers. The centers of the first family, which are relatively unstable kinetically, are capable of polymerizing and copolymerizing all olefins. This family includes from four to six populations of centers that differ in their stereospecificity, average molecular weights of polymer molecules they produce, and in the values of reactivity ratios in olefin copolymerization reactions. The centers of the second family (two populations of centers) efficiently polymerize only ethylene. They do not homopolymerize ␣-olefins and, if used in ethylene/␣-olefin copolymerization reactions, incorporate ␣-olefin molecules very poorly.

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“…In this study, we took MCM-41 and SBA-15 as support materials, respectively, to immobilize TiCl 4 for the synthesis of polyethylene with special property. Ordinarily, there were three methods to synthesize the TiCl 4 /MgCl 2 /SiO 2 catalyst system [10][11][12]. Here, we used CH 3 MgCl as scavenger to remove the hydroxyl on the surface to increase the catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Nanofibrous ultrahigh molecular weight polyethylene synthesized using TiCl4 as catalyst supported on MCM-41 and SBA-15

Lei

Wang

et al. 2011

Polym. Bull.

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Nanofibrous ultrahigh molecular weight polyethylene (UHMWPE) was synthesized via Ziegler-Natta catalyst anchoring on MCM-41 and SBA-15 as supported catalysts, respectively. These supported catalysts exhibited high activity at different temperatures and Al/Ti ratios, and showed different polymerization kinetics behaviors which were well explained by their different pore structures. The ultrahigh molecular weight of polyethylene might be due to the restrained spaces of the supported catalysts mesopores prohibiting the polymer chains transfer reaction. The obtained nanofibrous morphology might be for the high enough stress generated in the mesopores extruding the polymer out to form.

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Copolymerization of ethylene and propylene over the SiO2-supported MgCl2/TiCl3 catalyst

Cited by 30 publications

References 5 publications

Propylene polymerization with catalysts containing divalent titanium

Propylene polymerization with catalysts containing divalent titanium

Multicenter nature of titanium‐based Ziegler–Natta catalysts: Comparison of ethylene and propylene polymerization reactions

Nanofibrous ultrahigh molecular weight polyethylene synthesized using TiCl4 as catalyst supported on MCM-41 and SBA-15

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