Modeling of Synthesis and Flow Properties of Propylene–Diene Copolymers

Das, Chinmay; Read, Daniel J.; Soulages, Johannes; Shirodkar, Pradeep

doi:10.1021/ma5011205

Cited by 9 publications

(11 citation statements)

References 42 publications

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“…Phenomenologically both M e and τ e have been found to vary systematically with the comonomer content . Also ring formation from diene has been implicated in variation of τ e . As our results in the previous section show, one can decrease the amount of incorporated diene by increasing the time of reaction (or residence time).…”

Section: Dynamic Scalingsupporting

confidence: 73%

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Static and Dynamic Scaling Close to Gelation in Chain‐Polymerization: Effect of Reactor Type

Das

Read

Soulages

et al. 2017

Macro Theory & Simulations

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Because of the familiarity of gelation theories in polycondensation reaction of multifunctional groups, often the gel‐point is defined as the point of diverging weight averaged molar mass. The authors present an industrially relevant counter‐example to this common perception. Chain‐growth polymerization in realistic reactors introduces history dependent crosslinking probability. For copolymerization of a two functional monomer (ethylene) with a four functional comonomer (nonconjugated diene), the authors show from a Monte Carlo scheme that standard gelation scaling exponents remain valid for a semibatch reactor. However, for syntheses in a continuous stirred tank reactor (CSTR), all commonly measured molar mass moments (number, weight and “z”‐averaged moment) remain finite at the gel‐point; the first moment to diverge is the fourth moment. Hence, identification of the gel point from experimental observations is difficult, and cannot be achieved through monitoring of the weight averaged molar mass. The authors use a numerical scheme based on the tube model of polymer melts to predict the rheology of the generated molecules. Stress relaxation follows a power‐law decay, but due to dynamic dilution effects the CSTR resins exhibit much slower increase in the zero shear viscosity as the gel point is approached as compared to the semibatch reactor resins.

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Section: Dynamic Scalingsupporting

confidence: 73%

“…We consider a set of reaction steps that has been used to describe polymerization of polyolefins with metallocene catalysts, supplemented by reaction steps involving nonconjugated diene . Schematically the reaction steps are shown in Figure .…”

Section: Monte Carlo Schemementioning

confidence: 99%

Static and Dynamic Scaling Close to Gelation in Chain‐Polymerization: Effect of Reactor Type

Das

Read

Soulages

et al. 2017

Macro Theory & Simulations

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“…The typical elution curves of the copolymers by SEC with triple detectors were shown in Fig. 21 The weight average LCBD for each sample was calculated and the result was summarized in Table 2 and Table S3. Only one peak was observed in RI elution curve.…”

Section: Characterization Of Lcbpps By Sec With Triple Detectorsmentioning

confidence: 99%

“…13 Generally, the grafting method involved multiple post-polymerization procedures and extra separation to obtain pure LCBPPs. [18][19][20][21] However, the copolymerization behaviors of propylene with non-conjugated diolefins are extremely complicated. However, only a few specific catalysts which can effectively produce vinyl-ended macro-monomer through -methyl elimination and incorporate it into polymer chain have been discovered.…”

Section: Introductionmentioning

confidence: 99%

Copolymerization of propylene with Si-containing α,ω-diolefins: how steric hindrance of diolefins affects long chain branch formation

Wang

Zhang

et al. 2016

Polym. Chem.

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By using pyridylamido-hafnium/[Ph3C][B(C6F5)4]/Al i Bu3 catalytic system, a series of long chain branched isotactic polypropylenes (LCBPPs) were in situ synthesized by copolymerization of propylene with Si-containing monomers 4,4-dimethyl-4-sila-1,6-heptadiene (DMS), 4-methyl-4-phenyl-4-sila-1,6-heptadiene (MPS), 4,4-diphenyl-4-sila-1,6-hepta-diene (DPS), or 4-methyl-4-vinyl-4-sila-1,6-heptadiene (MVS). The effects of the substituent groups on copolymerization behavior and topological structure were further investigated. The substituent groups decreased the cyclization tendency of the diallylsilane, which increased the probability of the insertion of the pendent vinyl groups into other polymer chain. Thus, LCBPPs could be easily prepared under mild conditions by exquisitely controlling comonomer structure and polymerization conditions such as initial concentration of comonomer, the dosage of chain transfer agent (CTA) and reaction time. The presence of LCB structure was confirmed by characterization of SEC equipped with triple detectors, small-amplitude dynamic rheological measurements and uniaxial extension. The introduction of LCBs endowed PP with improved rheological behavior and melt strength, which made the resultant LCBPPs possess potential application in thermal process such as blow molding and foaming. A series of long chain branched isotactic polypropylenes (LCBPPs) were in situ synthesized by copolymerization of propylene with diallylsilanes. The substituent groups can efficiently suppress cyclization of the diolefin and significantly improve LCB formation efficiency during the copolymerization of propylene and diallylsilane.

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“…Earlier work made use of the method of moments. More recent work has looked at coupling again, using methods like Monte Carlo and Numerical Fractionation which is an extension of the method of moments. These have all centered around catalyzed olefin copolymerization using diene comonomers like ethylidene norbornene.…”

Section: Introductionmentioning

confidence: 99%

Network Formation by Free Radical Polymerization in Isothermal Continuous Flow Stirred Reactors

Nieves‐Remacha

Villa

Arriola

2016

Macro Reaction Engineering

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The authors apply the method of moments to the study of network formation in continuous flow stirred reactors when chain transfer to polymer and coupling are present in the reaction scheme. This approach leads to analytical solutions for the various moments involved. The authors start by assuming that the rate of coupling is proportional to the length of dead chains, which allow them to review and extend previous work in this area. This is followed by similar derivations when a coupling agent is present and the rate of coupling is proportional to the number of coupling groups that such agent leaves in dead polymer molecules, demonstrating that higher values of second order moments can be reached at lower levels of unreacted coupling agent.

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Modeling of Synthesis and Flow Properties of Propylene–Diene Copolymers

Cited by 9 publications

References 42 publications

Static and Dynamic Scaling Close to Gelation in Chain‐Polymerization: Effect of Reactor Type

Static and Dynamic Scaling Close to Gelation in Chain‐Polymerization: Effect of Reactor Type

Copolymerization of propylene with Si-containing α,ω-diolefins: how steric hindrance of diolefins affects long chain branch formation

Network Formation by Free Radical Polymerization in Isothermal Continuous Flow Stirred Reactors

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