Copolymerization of ethylene and non-conjugated dienes with Cp2ZrCl2/MAO catalyst system: effect of polymerization temperature on the copolymer structure

Pietikäinen, Pirjo; Seppälä, Jukka; Ahjopalo, L.; Pietilä, Lars‐Olof

doi:10.1016/s0014-3057(99)00053-1

Cited by 44 publications

(31 citation statements)

References 25 publications

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“…Polypropylene (PP) polymerisation using most metallocene catalysts, typically propagated through 1,2 insertion and terminated by β-hydrogen elimination, leads to a sterically congested vinylidene chain-end that prohibits further inclusion in another growing chain 5,6 . Copolymerisation with non-conjugated dienes 7-9 offers a viable route to introduce LCB in one-step PP synthesis and to enhance amount of LCB during polyethylene synthesis using catalysts that allow macromonomer insertion 10,11 .…”

Section: Introductionmentioning

confidence: 99%

Modeling of Synthesis and Flow Properties of Propylene–Diene Copolymers

et al. 2014

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Copolymerisation with non-conjugated dienes offers an attractive route for introducing long-chain branching in polypropylene. From a simplified set of rate equations for such copolymerisation with a metallocene catalyst, we derive the probabilities of branch formation at different stages of the reaction in a semi-batch reactor. Using these probabilities, we generate an ensemble of molecules via a Monte Carlo sampling.The knowledge of the branching topology and segment lengths allows us to compute the flow properties of the resins from computational rheology. We compare our model predictions with existing experimental data, namely the molar mass distribution and small angle oscillatory shear response, for a set of resins with varying diene content. * To whom correspondence should be addressed 1The rheology data suggests that the entanglement time τ e depends sensitively and in a well-defined fashion on the diene content.

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Section: Introductionmentioning

confidence: 99%

Modeling of Synthesis and Flow Properties of Propylene–Diene Copolymers

et al. 2014

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“…The copolymerization of non-conjugated dienes with ethylene or a-olefins often produces polymers with uncyclized units, because the reactivity of ethylene and a-olefins is greater than that of non-conjugated dienes, which results in the preferential insertion of monomers over the cyclization of the diene unit at the end of the growing chain. [35][36][37][38][39][40][41][42][43][44][45][46] In contrast to early transition metal complexes, late transition metal complexes are highly active for the oligomerization of ethylene but are not suitable for polymerization. However, in 1995, Brookhart reported that Pd and Ni complexes with diimine ligands show high catalytic activity for the polymerization of ethylene, propylene and aolefins.…”

Section: Introductionmentioning

confidence: 99%

Stereo-controlled synthesis of polyolefins with cycloalkane groups by using late transition metals

Takeuchi

2012

Polym J

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Pd complexes with diimine ligands promoted the controlled cyclopolymerization of 1,6-dienes and 1,6,11-trienes to afford polymers containing 1,2-trans-cyclopentane groups with well-regulated stereochemistry. The polymerization proceeded with quantitative cyclization of the monomer, even under bulk conditions or in copolymerization reactions with ethylene and aolefins. The polymerization of monomers with oligomethylene spacers yielded polymers with five-membered rings that are accurately distributed along the polymer chain. 4-Alkylcyclopentenes and alkenylcyclohexanes were also polymerized by Pddiimine complexes to afford polymers with 1,3-trans-cyclopentane groups and 1,4-trans-cyclohexane groups, respectively. Pd complexes with a C 2 symmetrical structure promoted the isospecific polymerization of 4-alkylcyclopentenes, and the resultant isotactic polymers showed liquid crystalline properties. The mechanism of the polymerization reaction has been revealed.

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“…In this sense, Pietikä inen and coworkers observed a similar behaviour studying the effect of reaction temperature on the copolymerization of ethylene with several dienes. [21,22] These authors showed that the decrease in reaction temperature from 80 to 50 8C led to a higher amount of diene in the product since the reactivity of ethylene decrease more strongly than the reactivity of dienes. Similar trend seems to be observed in this case but using 1-butene as comonomer.…”

Section: Resultsmentioning

confidence: 99%

Ethylene/1‐Butene Copolymerization over Heterogeneous Metallocene Catalyst

Grieken

Martı́n

Moreno

et al. 2007

Macromolecular Symposia

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Summary: Nowadays, bimodal polyethylene obtained in a two step cascade process is a matter of intensive research in polyolefin field. In the second stage of this process, a high molecular weight ethylene-a-olefin copolymer is formed over the homopolymer produced in the first step. In this work, a study of reaction variables on this second step using an heterogeneous metallocene catalyst was carried out. The effect of reaction temperature (70-85 8C) and comonomer concentration (0-0.32 mol/l) was evaluated. Polymerization results showed that activity increases with temperature and 1-butene initial concentration. Moreover, higher comonomer concentrations and lower temperatures involve higher short chain branching (SCB). Copolymers characterization indicated that melt temperature and density values have a lineal decrease with the SCB content in the polymer, regardless of the reaction temperature. As well, for every temperature, higher comonomer concentrations do not seem to affect to molecular weight, whereas a decrease of crystallinity was observed, which may explain the increase of catalyst activity.

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Copolymerization of ethylene and non-conjugated dienes with Cp2ZrCl2/MAO catalyst system: effect of polymerization temperature on the copolymer structure

Cited by 44 publications

References 25 publications

Modeling of Synthesis and Flow Properties of Propylene–Diene Copolymers

Modeling of Synthesis and Flow Properties of Propylene–Diene Copolymers

Stereo-controlled synthesis of polyolefins with cycloalkane groups by using late transition metals

Ethylene/1‐Butene Copolymerization over Heterogeneous Metallocene Catalyst

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