On the Discrimination of <scp>RAFT</scp> Models Using Miniemulsion Polymerization

Tobita, Hidetaka

doi:10.1002/mats.201300111

Cited by 10 publications

(18 citation statements)

References 28 publications

(105 reference statements)

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“…On the basis of the numerical calculations, using a wide range of parameters, it was concluded that the SF model does not show the polymerization rate increase by decreasing the particle size [23], as long as the given set of parameters cause the retardation behavior in bulk polymerization. Figure 7a,b show the simulation results for the conversion development during bulk and miniemulsion polymerization, by using the same set of parameters as in Figure 6.…”

Section: )mentioning

confidence: 99%

Effect of Small Reaction Locus in Free-Radical Polymerization: Conventional and Reversible-Deactivation Radical Polymerization

Tobita

2016

Polymers

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Abstract:When the size of a polymerization locus is smaller than a few hundred nanometers, such as in miniemulsion polymerization, each locus may contain no more than one key-component molecule, and the concentration may become much larger than the corresponding bulk polymerization, leading to a significantly different rate of polymerization. By focusing attention on the component having the lowest concentration within the species involved in the polymerization rate expression, a simple formula can predict the particle diameter below which the polymerization rate changes significantly from the bulk polymerization. The key component in the conventional free-radical polymerization is the active radical and the polymerization rate becomes larger than the corresponding bulk polymerization when the particle size is smaller than the predicted diameter. The key component in reversible-addition-fragmentation chain-transfer (RAFT) polymerization is the intermediate species, and it can be used to predict the particle diameter below which the polymerization rate starts to increase. On the other hand, the key component is the trapping agent in stable-radical-mediated polymerization (SRMP) and atom-transfer radical polymerization (ATRP), and the polymerization rate decreases as the particle size becomes smaller than the predicted diameter.

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Section: )mentioning

confidence: 99%

Effect of Small Reaction Locus in Free-Radical Polymerization: Conventional and Reversible-Deactivation Radical Polymerization

Tobita

2016

Polymers

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“…Theoretical investigation have clarified the rate difference quantitatively, and the equation predicting the threshold diameter below which significant acceleration occurs was derived . As reviewed in the theoretical section, the relationship between the miniemulsion polymerization rate and the droplet size has been elucidated theoretically . In the present article, the experiment was designed on the basis of the theoretical predictions.…”

Section: Introductionmentioning

confidence: 99%

“…Even for such a hybrid model, the determined model parameters could be classified into SF and IT, depending on the major reason for retardation. If the determined equilibrium constant k 1 / k 2 cannot cause retardation, the major reason for retardation would be the intermediate termination . Such cases could be considered belonging to the IT model.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Method to Discriminate RAFT Models between Intermediate Termination and Slow Fragmentation via Comparison of Rates of Miniemulsion and Bulk Polymerization

Suzuki

Kanematsu

Miura

et al. 2014

Macro Theory & Simulations

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A simple model discrimination method for RAFT polymerization mechanism, proposed on a theoretical basis, is applied to the polystyryl dithiobenzoate‐mediated styrene polymerization. It is confirmed that the intermediate termination (IT) is the major reason for the rate retardation. The method utilizes the theoretical finding that the IT model shows a significantly larger polymerization rate in miniemulsion compared with the corresponding bulk polymerization, while the slow fragmentation model does not change the polymerization rate. The miniemulsion polymerization rate increases as the droplet size is made smaller, which agrees reasonably well with the theoretical prediction. The present model discrimination method is easy to apply, and would provide great insight into both basic and applied research in RAFT polymerization.

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“…Even though RAFT polymerizations have been studied extensively, there is an ongoing debate regarding particular aspects of the kinetic mechanism. It has been observed that for certain RAFT agents, such as dithiobenzoates and some dithiocarbamates, there is rate retardation when the concentration of the RAFT agent is increased, as well as an induction period.…”

Section: Introductionmentioning

confidence: 99%

Modeling of RAFT Polymerization using Probability Generating Functions. Detailed Prediction of Full Molecular Weight Distributions and Sensitivity Analysis

Fortunatti

Sarmoria

Brandolin

et al. 2014

Macro Reaction Engineering

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A mathematical model of RAFT polymerization processes is presented capable of predicting the full molecular weight distribution (MWD) through the use of probability generating functions (pgf). The bivariate distribution of the intermediate RAFT species is calculated. The model is able to work with the three kinetic mechanisms currently under discussion for explaining the observed behavior of this type of polymerization. For comparison purposes, the population balances are also solved by direct integration of the resulting equations. The results show that the pgf technique allows obtaining accurate solutions with very small computational times for systems of any average molecular weight. Spurious oscillations observed in the high molecular weight tail of the MWD can be easily disregarded. A sensitivity analysis over several of the kinetic constants is also performed, showing the effects of changing their values over several orders of magnitude. This analysis aims to showcase the enormous potential of the pgf technique for modeling and optimization of complex polymerization kinetics.

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On the Discrimination of RAFT Models Using Miniemulsion Polymerization

Cited by 10 publications

References 28 publications

Effect of Small Reaction Locus in Free-Radical Polymerization: Conventional and Reversible-Deactivation Radical Polymerization

Effect of Small Reaction Locus in Free-Radical Polymerization: Conventional and Reversible-Deactivation Radical Polymerization

Experimental Method to Discriminate RAFT Models between Intermediate Termination and Slow Fragmentation via Comparison of Rates of Miniemulsion and Bulk Polymerization

Modeling of RAFT Polymerization using Probability Generating Functions. Detailed Prediction of Full Molecular Weight Distributions and Sensitivity Analysis

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