Ethylene‐butadiene copolymers, 2. Long branching, double bond distribution and their effect on polymer properties

Bruzzone, M.; Giuliani, G.; Paiella, Roberto

doi:10.1002/macp.1978.021790907

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…At higher temperatures, homogeneous vanadium catalysts (VOCl 3 or VCl 4 /Al[N(CH 3 ) 2 ] 3 /Al(C 2 H 5 )Cl 2 ) have been reported to copolymerize dienes and olefins by ENICHEM researchers. The distribution of the butadiene monomeric units, though nonrandom, was sufficiently homogeneous at low monomeric unit content of butadiene (1–3 mol %). − …”

Section: Copolymerization Of 13-dienes With α-Olefinsmentioning

confidence: 95%

Dienes Polymerization: Where We Are and What Lies Ahead

Ricci¹,

Pampaloni

Sommazzi

et al. 2021

Macromolecules

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Recently, the research activity in the field of the stereospecific polymerization of conjugated dienes has focused on the use of catalysts based on organometallic complexes having a well-defined structure and containing ligands of various types (e.g., phosphines, bis-imines, and pyridylimines), since it has been observed that the nature of the ligand, as expected on the basis of the diene polymerization mechanism proposed several years ago by Porri, is able to exert a strong influence on the polymerization regioand stereoselectivity, on the polymer molecular weights and their distribution, and in some cases to impart a living feature to the catalysts themselves. In this Perspective we highlight the most recent results obtained in this field and discuss possible future developments in this area.

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Section: Copolymerization Of 13-dienes With α-Olefinsmentioning

confidence: 95%

Dienes Polymerization: Where We Are and What Lies Ahead

Ricci¹,

Pampaloni

Sommazzi

et al. 2021

Macromolecules

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show abstract

“…The first copolymerization of E and BD was reported by Natta . Homogeneous vanadium and heterogeneous titanium systems have been shown to copolymerize E and BD at room temperature and above, giving polymers with a multiblock structure and low incorporation of BD. Most metallocene catalysts display low activities and tend to generate copolymers that contain a mixture of unsaturated 1,4-enchained BD and methylene−1,2-cyclopentane units …”

Section: Introductionmentioning

confidence: 99%

Heterogenized “Ligand-Free” Lanthanide Catalysts for the Homo- and Copolymerization of Ethylene and 1,3-Butadiene

et al. 2005

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Silica-supported lanthanide catalysts have been prepared from the reaction of dehydroxylated silica and tris(bistrimethylsilyl)amido lanthanides Ln[N(SiMe 3)2]3 (Ln ) Sc, Y, La, Nd, Sm, Gd, Dy). On activation with Al i Bu3 (TIBA), the compounds catalyze the polymerization of ethylene, with the scandium catalyst showing the highest activity. There is an inverse relationship between ionic radius of the lanthanide metal and the activity of the resulting catalyst. The polymer produced was highly linear and of high molecular weight. Activation with magnesium alkyls was less effective but gave polyethylene of slightly higher molecular weight. The supported lanthanides, when activated with TIBA, were also active for the polymerization of 1,3-butadiene, with very high molecular weight polymers being produced. In all cases the polymer was found to be predominately 1,4-cis (typically 85-90% by diad analysis), with only scandium producing a much higher level of 1,4-trans units. The system was also shown to copolymerize ethylene and butadiene, with large differences in the polymeric products depending on the both the choice of the lanthanide and the feed ratio of the monomer. With both neodymium and dysprosium multiblock polymers consisting of 1,4-cis, 1,4-trans, and ethylene blocks were obtained. With scandium two distinct modes of polymerization were detected, with both multiblock 1,4-cis and a somewhat alternating ethylene/1,4-trans block structure observed in the 13 C NMR spectra.

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Ethylene‐butadiene copolymers, 1. Preparation with modified vanadium catalysts

1978

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The copolymerization of ethylene with 1,3-butadiene to give crystalline, homopolymer-free, high molecular weight, substantially linear copolymer is described. Butadiene polimerizes almost exclusively in a trans-l,4 structure, ranging in content from zero to 50 mole-%. At relatively low content of butadiene monomeric units ( 5 3 0 mole-%) X-ray crystallinity is of polyethylene type with a slight variation of the structural parameters. At higher levels of butadiene monomeric units, crystallinity of rrans-1,4-polybutadiene is also observed. The products with little unsaturation (1-5 mole-%) melt at about 132°C and are able to crosslink with sulfur-based recipes. A 13C'NMR study shows a block-type structure, but the copolymer appears homogeneous in composition. The product of the reactivity ratios was evaluated. The catalyst system consists of vanadium tris(acetylacetonate), diethylaluminium chloride, and an acidic compound or its precursor. The nature and the amount of the acidic modifier regulate the polymerization rate as well as the molecular weight, composition, and long branching of the copolymer, so that a strict control of the catalyst system is required. The behaviour of the catalyst is tentatively explained by the polarity of the active carbon-vanadium bond, which depends on substituents and complexing agents. Pritchard et

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Ethylene‐butadiene copolymers, 2. Long branching, double bond distribution and their effect on polymer properties

Cited by 4 publications

References 11 publications

Dienes Polymerization: Where We Are and What Lies Ahead

Dienes Polymerization: Where We Are and What Lies Ahead

Heterogenized “Ligand-Free” Lanthanide Catalysts for the Homo- and Copolymerization of Ethylene and 1,3-Butadiene

Ethylene‐butadiene copolymers, 1. Preparation with modified vanadium catalysts

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