Molecular Weight Distribution in Emulsion Polymerization

Tobita, Hidetaka; Takada, Yuko; Nomura, Mamoru

doi:10.1021/ma00092a020

Cited by 66 publications

(62 citation statements)

References 7 publications

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“…[19] based on the competition technique [39,40] developed for conventional emulsion polymerization, which works much faster than the usual types of MC simulation methods, in which monomer units are added one-by-one to each growing chain. In the competition technique, the imaginary times of various events occurring in a polymer particle are calculated, then the shortest imaginary time is chosen as a real event.…”

Section: Appendix -Outline Of the MC Simulation Methodsmentioning

confidence: 99%

RAFT Miniemulsion Polymerization Kinetics, 1 – Polymerization Rate

Tobita

2009

Macro Theory & Simulations

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The polymerization kinetics of a RAFT-mediated radical polymerization inside submicron particles (30 < D p < 300 nm) is considered. When the time fraction of active radical period, f A , is larger than ca. 1%, the polymerization rate increases with reducing particle size, as for the cases of conventional emulsion polymerization. The rate retardation by the addition of RAFT agent occurs with or without intermediate termination in zero-one systems. For the particles with D p < 100 nm, the statistical variation of monomer concentration among particles may not be neglected. It was found that this monomerconcentration-variation (MCV) effect may slow down the polymerization rate. An analytical expression describing the MCV effect is proposed, which is valid for both RAFT and conventional miniemulsion polymerizations.

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Section: Appendix -Outline Of the MC Simulation Methodsmentioning

confidence: 99%

RAFT Miniemulsion Polymerization Kinetics, 1 – Polymerization Rate

Tobita

2009

Macro Theory & Simulations

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“…In this case, Equation (5) leads to the threshold diameter, d p1q p,R = 252 nm. Figure 2 shows the calculated results based on the Monte Carlo (MC) simulation method proposed in [3,12], with k p = 500 L¨mol´1¨s´1. It is clearly shown that the polymerization rate increases significantly for d p < 250 nm, which shows excellent agreement with Equation (5).…”

Section: Conventional Free-radical Polymerizationmentioning

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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“…[129][130][131] The important difference is that, in microscopic stochastic modeling, differential equations are not required. Microscopic stochastic modeling comprises methods with different degrees of complexity: methods with only temporal resolution such as those Monte Carlo approaches previously used to describe radical polymerization reactions, [132][133][134][135][136] methods with temporal and spatial resolution, [137,138] and methods with single-molecule temporal and spatial resolution. [139] Because of its discrete nature this approach is ideally suited for heterogeneous reaction systems where reactants of very different size and mobility participate.…”

Section: Microscopic Modelingmentioning

confidence: 99%

Molecular Aspects of Radical Polymerizations—The Propagation Frequency

Tauer

Hernández

2010

Macromol. Rapid Commun.

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The product of the propagation rate constant and monomer concentration is a central issue of radical polymerization. Both quantities are strongly interrelated as the determination of a reliable value of the propagation rate constant requires exact knowledge of the monomer concentration. Even for homogeneous polymerization conditions, exact knowledge of the monomer concentration at the reaction site from the molecular perspective is not trivial. For emulsion polymerizations the situation is additionally complicated by mass transfer events and colloid-chemical effects. Molecular modeling appears as an attractive alternative or complement to the deterministic kinetic description of radical polymerizations.

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Molecular Weight Distribution in Emulsion Polymerization

Cited by 66 publications

References 7 publications

RAFT Miniemulsion Polymerization Kinetics, 1 – Polymerization Rate

RAFT Miniemulsion Polymerization Kinetics, 1 – Polymerization Rate

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

Molecular Aspects of Radical Polymerizations—The Propagation Frequency

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