Polymerization of higher linear ?-olefins with (CH3)2Si(2-methylbenz[e]indenyl)2ZrCl2

Brüll, Robert; Pasch, Harald; Raubenheimer, Helgard G.; Sanderson, Ronald D.; Wahner, Udo M.

doi:10.1002/1099-0518(20000701)38:13<2333::aid-pola50>3.0.co;2-l

Cited by 33 publications

(8 citation statements)

References 19 publications

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“…Similarly, Wahner et al 19 showed that high molecular weight poly(␣-olefins) could be made with this catalyst. We expected, therefore, to synthesize high molecular weight polymers, and this is illustrated by the values given in Table II.…”

Section: Reaction Mixtures Molecular Weights and Distributionsmentioning

confidence: 99%

“…[12][13][14][15][16][17][18] In particular, Arnold et al 17 showed that with the catalyst Et(Ind) 2 HfCl 2 /MAO, copolymers of propylene with some of the higher ␣-olefins could be obtained with reasonable molecular weights. Wahner et al 19 recently showed that with the catalyst rac-Me 2 Si(2-MeOBenz[e]Ind) 2 ZrCl 2 /MAO, high molecular weight polymers of the higher linear ␣-olefins could be obtained. This prompted us to investigate the copolymerization of propylene and the higher linear ␣-olefins with the C 2 symmetric metallocene rac-Me 2 Si(2-MeOBenz[e]Ind) 2 ZrCl 2 /MAO catalyst system.…”

Section: Introductionmentioning

confidence: 99%

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The copolymerization of propylene with higher, linear ?-olefins

Reenen

Brüll

Wahner

et al. 2000

J. Polym. Sci. A Polym. Chem.

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Section: Reaction Mixtures Molecular Weights and Distributionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The copolymerization of propylene with higher, linear ?-olefins

Reenen

Brüll

Wahner

et al. 2000

J. Polym. Sci. A Polym. Chem.

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“…Extraction in boiling heptane was employed to separate atactic polyoctadecene from isotactic polyoctadecene. , Thus, extracted atactic polyoctadecene can crystallize by self-assembly of their side chains into ordered rotator phases . More recently, C 2 symmetric metallocene catalysts activated with methylaluminoxane have been employed to prepare isotactic polyolefins from poly(1-butene) to poly(1-octadecene). , Only thermal properties of these metallocene-catalyzed isotactic polyolefins were reported; however, the examination of their melt and crystalline structures is lacking. The crystalline structure of ZN-catalyzed isotactic polyoctadecene (iPOD), in the presence of crystallizable atactic polyoctadecene (aPOD), has been thoroughly examined by Turner-Jones using wide-angle X-ray diffraction (WAXD), and two different crystalline forms, type I and II, were reported in nonpurified iPOD depending on thermal history.…”

Section: Introductionmentioning

confidence: 99%

Microstructure of Crystallizable α-Olefin Molecular Bottlebrushes: Isotactic and Atactic Poly(1-octadecene)

et al. 2018

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Isotactic and atactic poly(1-octadecene) (iPOD and aPOD) have been synthesized by organometallic coordinative insertion polymerization of 1-octadecene. Analyzing X-ray and neutron scattering data of POD melts identifies their bottlebrush structures as flexible rods where the rod length is the extended backbone length and rod radius is the side chain coil dimension. Upon cooling, both iPOD and aPOD melts crystallize by fully extending their coiled side chains to form orthorhombic alkane crystals in iPOD and nematically ordered rotator alkane crystals in aPOD, as determined by X-ray scattering and Raman spectroscopy. Molecular dynamics simulations of isotactic and atactic 48-mers of 1-octadecene were applied to define and verify melt and crystalline structures and scattering peak assignments, respectively. Modeling suggests that side chains of both crystallized isotactic and atactic PODs align at 70°and 160°to the 4/1 spiral backbone of equal probability, at an average of 115°, and POD chains pack in an antiparallel pattern. Large wheat-sheaf structural assembly of fibril bundles can be observed in aPOD, which render high opacity to these samples. Each of those fibrils is made of several bottlebrush molecules packed into a hexagonal lattice. Faster crystallization observed in iPODs hinders the formation of large crystallites, which results in translucent samples.

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“…6 The commonly used catalysts for a-olen polymerization mainly include Lewis acid catalysts, Ziegler Natta catalysts, metallocene catalysts, ionic liquid catalysts, etc. [7][8][9][10][11][12][13][14][15][16] Among them, Ziegler Natta catalysts are traditional and the most common catalyst for olen polymerization. [17][18][19] However, because Ziegler Natta catalysts have multiple active sites, olens have different growth rates at different sites of catalyst, and the various properties of polymerization cannot be effectively controlled.…”

Section: Introductionmentioning

confidence: 99%