Assessing the Importance of Diffusion‐Controlled Effects on Polymerization Rate and Molecular Weight Development in Nitroxide‐Mediated Radical Polymerization of Styrene

Roa‐Luna, Martha; Díaz‐barber, Martha Patricia; Vivaldo‐Lima, Eduardo; Lona, Liliane Maria Ferrareso; McManus, Neil T.; Penlidis, Alexander

doi:10.1080/10601320601031366

Cited by 26 publications

(33 citation statements)

References 30 publications

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“…In CRP processes, diffusional limitations on propagation have been mostly evaluated via the Bueche based 'serie' encounter pair model (entry 1 in Table 3 [42,62] ). For example, Roa-Luna et al [62] used this model to assess the importance of diffusional limitations on propagation in the reverse NMP of styrene (393 K) using TEMPO as deactivator and dibenzoyl peroxide (DBO) as conventional radical initiator t L y X 2 ; M t : transition metal; X halogen atom; L: ligand; n(þ1) oxidation number) in the presence of ATRP initiator R 0 X; i,j: chain length; X: endgroup functionality (EGF) k a,da,dis,p,t : rate coefficient for activation, deactivation, dissociation, propagation and termination.…”

Section: Diffusional Limitations On Propagationmentioning

confidence: 99%

The Crucial Role of Diffusional Limitations in Controlled Radical Polymerization

D’hooge

Reyniers

Marin

2013

Macro Reaction Engineering

124

146

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The importance of diffusional limitations in controlled radical polymerization at laboratory scale and in homogeneous medium is highlighted using different diffusion models. In particular, a coupled ‘parallel’ encounter pair model is introduced which allows a rigorous description of the influence of diffusional limitations on the activation/deactivation process. Diffusional limitations on termination have a significant influence, whereas those on the activation/deactivation process can disturb the regular growth pattern at high conversion if the mediating agent is a sufficiently bulky species. Diffusional limitations on initiation are only important in case radical initiator is still present at high conversion.

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Section: Diffusional Limitations On Propagationmentioning

confidence: 99%

The Crucial Role of Diffusional Limitations in Controlled Radical Polymerization

D’hooge

Reyniers

Marin

2013

Macro Reaction Engineering

124

146

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“…The polymerization mechanism used in this work is the same as the one proposed by Bonilla et al16 However, we did not use their model as in some of our previous contributions on NMRP 21, 23, 24. Instead, we modeled the polymerization system using the Predici commercial software.…”

Section: Modelingmentioning

confidence: 99%

“…The effects of diffusion‐controlled (DC) reactions on controlled radical polymerization (CRP) processes have not been studied and understood as systematically as in standard free‐radical polymerization. Some authors have considered these effects negligible for NMRP due to the low molecular weights typical of CRP, others only consider DC‐termination in a semiempirical fashion,15, 18, 19 and others consider that the reactions of propagation, activation, and deactivation of polymer radicals may also become DC 20, 21. Chevalier et al22 carried out an experimental study on the effect of dilution on the termination kinetic rate constant, k t , in the NMRP of styrene, using N ‐ tert ‐butyl‐ n ‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐ n ‐oxyl (SG1), at 120°C, and found that k t was independent of viscosity build‐up induced by monomer conversion, but there seemed to be a dependence of the value of k t on the initial dilution of the system.…”

Section: Introductionmentioning

confidence: 99%

“…The first stage of this study was to expand and validate23 a previously derived16 kinetic model, using experimental data from our laboratories, now reported in the literature 24. This was followed by modifying the model with the incorporation of DC effects 21. Because DC effects seemed to be weak in NMRP, physical means to promote them were also attempted.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the addition of inert or TEMPO‐capped prepolymer on polymerization rate and molecular weight development in the nitroxide‐mediated radical polymerization of styrene

Roa‐Luna

Nabifar

McManus

et al. 2008

J of Applied Polymer Sci

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ABSTRACT:The importance of diffusion-controlled (DC) effects on controlled radical polymerization (CRP) processes has been rather controversial and usually considered only if there is some mismatch between experimental data and model predictions of polymerization rate and molecular weight averages. Results from an experimental study designed to create conditions in which DC effects may be present from the outset for the bimolecular nitroxide-mediated radical polymerization (NMRP) of styrene in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and dibenzoyl peroxide (BPO), are presented herein. The experiments consisted of adding size exclusion chromatography (SEC) polystyrene (PS) standards or nitroxyl-capped PS (of different molecular weights, in several proportions), to a conventional recipe of bimolecular NMRP of styrene, and studying the effect of their presence on polymerization rate and molecular weight development. A previously developed kinetic model for NMRP of styrene was modified to take into account the presence of prepolymer as an inert ''solvent,'' or as a monomolecular ''controller'' of high molecular weight. The effects of DC reactions (propagation, termination, activation, and deactivation of polymer radicals) were modeled using conventional free-volume theory. Reasonably, good agreement between experimental data and model predictions with either modeling approach was obtained. It was concluded that DC effects are weak in the NMRP of styrene, even in the presence of prepolymer.

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“…Some authors also considered diffusional limitations in controlled radical polymerizations on other reaction steps than termination, such as propagation and deactivation 17, 39. For ATRP, Delgadillo‐Velázquez et al17 account for diffusional limitations on a reaction step by considering a difference in diffusional barrier for the attraction and the separation of the reactants.…”

Section: Introductionmentioning

confidence: 99%

Methodology for Kinetic Modeling of Atom Transfer Radical Polymerization

D’hooge

Reyniers

Marin

2009

Macro Reaction Engineering

134

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A methodology for kinetic modeling of atom transfer radical polymerization is developed allowing to calculate the monomer conversion, the fraction of polymer molecules having end group functionality, the full molar mass distribution (MMD) of the dormant polymer and the number, mass, and z based average molar mass of the dead and dormant polymer. The developed methodology is based on an extension of the method of moments and allows an accurate description of the contribution of the polymer molecules with a high molar mass to the MMD of the polymer. Diffusional limitations on all considered reaction steps are systematically accounted for. Simulation results are in good agreement with experimental observations. Moreover, the methodology allows a detailed description of the broadness and the skewness of the MMD of the polymer.

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Assessing the Importance of Diffusion‐Controlled Effects on Polymerization Rate and Molecular Weight Development in Nitroxide‐Mediated Radical Polymerization of Styrene

Cited by 26 publications

References 30 publications

The Crucial Role of Diffusional Limitations in Controlled Radical Polymerization

The Crucial Role of Diffusional Limitations in Controlled Radical Polymerization

Effect of the addition of inert or TEMPO‐capped prepolymer on polymerization rate and molecular weight development in the nitroxide‐mediated radical polymerization of styrene

Methodology for Kinetic Modeling of Atom Transfer Radical Polymerization

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