Consistent values of rate parameters in free radical polymerization systems. II. Outstanding dilemmas and recommendations

Buback, Michael; Gilbert, Robert G.; Russell, Gregory T.; Hill, David J. T.; Moad, Graeme; O’Driscoll, K. F.; Shen, Jiacong; Winnik, Mitchell A.

doi:10.1002/pola.1992.080300516

Cited by 222 publications

(179 citation statements)

References 30 publications

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“…25 However, this effect was not observed in the systems S-MMA with butane thiol nor in the system S-MA with either CBr 4 or butane thiol. 26 In this paper the technique recognized by the IUPAC working party 16 is applied to low-conversion emulsion copolymerizations of S and MA and of S and MMA. This technique, which is outlined in the next section, was applied before 2 in the case of the emulsion copolymerization of S and MA.…”

Section: Methods For Determining the Rate Of Chain Transfermentioning

confidence: 99%

“…[11][12][13] Despite having some disadvantages connected with the use of an average molar mass rather than the distribution, 14 this method has been widely used to obtain data as evidenced by the number of data presented in the Polymer Handbook. 15 The second method is a technique recognized by an IUPAC working party 16 to obtain reliable chain transfer rate constants from the MMD provided chain transfer is the main chain-stoppage mechanism. 14,17,18 This is the case at very low radical concentrations (low initiator concentrations) and in the high molar mass regime.…”

Section: Methods For Determining the Rate Of Chain Transfermentioning

confidence: 99%

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Cross-Chain Transfer Rate Constants of Styrene-Terminated Radicals to Methyl Acrylate and Methyl Methacrylate

et al. 1996

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The chain transfer-to-monomer dominated regime of the molar mass distribution of lowconversion emulsion copolymers of styrene and methyl acrylate and of styrene and methyl methacrylate of various compositions, prepared with varying initiator concentrations, was analyzed with size exclusion chromatography. By extrapolation of the values of the slope of the natural logarithm of the number molar mass distribution to zero initiator concentration, it was possible to determine the average chaintransfer coefficient as a function of composition. By calculation of the ratio of the concentrations of styreneterminated radicals and methyl (meth)acrylate-terminated radicals with an appropriate propagation model, the values of the cross-chain transfer rate constants of styrene-terminated radicals to methyl acrylate and methyl methacrylate could be deduced. These values were interpreted in the light of newly gained insights into radical propagation and transfer reactions.

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Section: Methods For Determining the Rate Of Chain Transfermentioning

confidence: 99%

Section: Methods For Determining the Rate Of Chain Transfermentioning

confidence: 99%

Cross-Chain Transfer Rate Constants of Styrene-Terminated Radicals to Methyl Acrylate and Methyl Methacrylate

et al. 1996

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“…Nowadays, PLP coupled with size exclusion chromatography (SEC) is the method recommended by the International Union of Pure and Applied Chemistry (IUPAC) for the measurements of propagation rate coefficients [19][20][21][22]. The propagation rate coefficients for various important monomers evaluated by PLP are listed in Table 1.…”

Section: Introductionmentioning

confidence: 99%

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

2015

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Throughout the last 25 years, computational chemistry based on quantum mechanics has been applied to the investigation of reaction kinetics in free radical polymerization (FRP) with growing interest. Nowadays, quantum chemistry (QC) can be considered a powerful and cost-effective tool for the kinetic characterization of many individual reactions in FRP, especially those that cannot yet be fully analyzed through experiments. The recent focus on copolymers and systems where secondary reactions play a major role has emphasized this feature due to the increased complexity of these kinetic schemes. QC calculations are well-suited to support and guide the experimental investigation of FRP kinetics as well as to deepen the understanding of polymerization mechanisms. This paper is intended to provide an overview of the most relevant QC results obtained so far from the investigation of FRP. A comparison between computational results and experimental data is given, whenever possible, to emphasize the performances of the two approaches in the prediction of kinetic data. This work provides a comprehensive database of reaction rate parameters of FRP to assist in the development of advanced models of polymerization and experimental studies on the topic.

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“…It is obvious that for this reason the modeling of termination kinetics will be an extremely complex problem to tackle. Therefore, it would be desirable if more detailed kinetic information could be obtained about this termination process, [4][5][6] enabling estimation of the relevance of specific parameters. This paper will mainly focus on one of the abovementioned parameters, i.e., the chain length of the macroradicals which are involved in the termination reaction.…”

Section: Introductionmentioning

confidence: 99%

A Theoretical Description of a Method for Model-Independent Determination of Bimolecular Chain-Length-Dependent Free-Radical-Termination Rate Coefficients

et al. 1997

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. (1997). A theoretical description of a method for model-independent determination of bimolecular chain-length-dependent free-radical-termination rate coefficients. Macromolecules, 30(22), 6743-6753. DOI: 10.1021/ma970288l General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. ABSTRACT: A theoretical description is given of a method for model-independent determination of bimolecular chain-length-dependent free-radical-termination rate coefficients. By on-line determination of the monomer concentration versus time in a time-resolved pulsed laser polymerization, the value of the termination rate coefficient kt i,i of the termination reaction between species of identical chain length can be determined in a very simple fashion. The key assumption in this kt determination is that the radical chain-length distribution that is generated with a laser pulse is extremely narrow, such that all chains can be considered as being identical in chain length. With computer simulations the effects of several processes which could undermine this key assumption were investigated. For the monomer methyl methacrylate (MMA) the effects of (i) a Poisson distribution of the polymerization events, (ii) chain transfer to monomer, and (iii) the presence of a background initiation process were investigated. For MMA, none of these processes interfere with the model-independent determination of the termination rate coefficients, as long as suitable experimental conditions are chosen, which follow from the simulations.

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Consistent values of rate parameters in free radical polymerization systems. II. Outstanding dilemmas and recommendations

Cited by 222 publications

References 30 publications

Cross-Chain Transfer Rate Constants of Styrene-Terminated Radicals to Methyl Acrylate and Methyl Methacrylate

Cross-Chain Transfer Rate Constants of Styrene-Terminated Radicals to Methyl Acrylate and Methyl Methacrylate

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

A Theoretical Description of a Method for Model-Independent Determination of Bimolecular Chain-Length-Dependent Free-Radical-Termination Rate Coefficients

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