Kinetic Modeling of ICAR ATRP

D’hooge, Dagmar; Konkolewicz, Dominik; Reyniers, Marie-Françoise; Marin, Guy; Matyjaszewski, Krzysztof

doi:10.1002/mats.201100076

Cited by 83 publications

(100 citation statements)

References 53 publications

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“…To reach a conversion of 0.90 only 2 h are needed at 10 ppm, whereas already 16 h are required in case 50 ppm is employed. In agreement with previous deterministic simulations on ICAR ATRP homopolymerization [22], too low ppm levels lead to FRP behavior, as a sufficient amount of deactivator is needed to ensure controlled activation-growth-deactivation cycles. For an initial Cu(II) amount of 10 ppm, as shown in Figure 4, the ATRP catalyst is mostly in its activator state and an almost zero deactivator concentration is obtained at high conversion.…”

Section: Batch Proceduressupporting

confidence: 90%

“…Except for reactions involving conventional radical initiator fragments, these intrinsic parameters are taken from a previous kinetic study on the related "normal" ATRP system [26]. For simplicity, a constant conventional radical initiator efficiency of 0.70 [22] is used and the activation/deactivation kinetic parameters related to the conventional radical initiator are taken equal to those of the secondary species. As indicated in a recent study on ICAR ATRP of styrene, it can be expected that these parameters have a very limited effect on the overall polymerization rate and control over polymer properties [27], justifying the previous assumption.…”

Section: Kinetic Modelmentioning

confidence: 99%

“…Originally, Matyjaszewski et al [18] introduced ICAR ATRP for the controlled synthesis of well-defined poly(methyl methacrylate) and polystyrene using Cu based ATRP catalysts. Later on, using a deterministic modeling approach, D'hooge et al [22] demonstrated that well-defined ICAR ATRP homopolymers can only be obtained in case a sufficiently low conventional radical initiator concentration and a sufficiently high deactivator concentration are considered, since otherwise FRP-like behavior is observed. For less active catalysts, single or multiple discrete addition(s) of conventional radical initiator can be required to ensure a high conversion.…”

Section: Introductionmentioning

confidence: 99%

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Fed-Batch Control and Visualization of Monomer Sequences of Individual ICAR ATRP Gradient Copolymer Chains

et al. 2014

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Based on kinetic Monte Carlo simulations of the monomer sequences of a representative number of copolymer chains (≈ 150,000), optimal synthesis procedures for linear gradient copolymers are proposed, using bulk Initiators for Continuous Activator Regeneration Atom Transfer Radical Polymerization (ICAR ATRP). Methyl methacrylate and n-butyl acrylate are considered as comonomers with CuBr 2 /PMDETA (N,N,N′,N′′,N′′-pentamethyldiethylenetriamine) as deactivator at 80 °C. The linear gradient quality is determined in silico using the recently introduced gradient deviation () polymer property. Careful selection or fed-batch addition of the conventional radical initiator I 2 allows a reduction of the polymerization time with ca. a factor 2 compared to the corresponding batch case, while preserving control over polymer properties ( ≈ 0.30; dispersity ≈ 1.1) . Fed-batch addition of not only I 2 , but also comonomer and deactivator (50 ppm) under starved conditions yields a below 0.25 and, hence, an excellent linear gradient quality for the dormant polymer molecules, albeit at the expense of an increase of the overall polymerization time. The excellent control is confirmed by the visualization of the monomer sequences of ca. 1000 copolymer chains.

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Section: Batch Proceduressupporting

confidence: 90%

Section: Kinetic Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fed-Batch Control and Visualization of Monomer Sequences of Individual ICAR ATRP Gradient Copolymer Chains

et al. 2014

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“…is the number-average chain length as defined by Equation (19). Also, ʋ is the free volume fraction, which is related to polymer concentration (Equation (25)) [29,30],…”

Section: Diffusion-controlled Reactionsmentioning

confidence: 99%

Modeling the Influence of Diffusion-Controlled Reactions and Residual Termination and Deactivation on the Rate and Control of Bulk ATRP at High Conversions

Rabea

Zhu

2015

Polymers

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Abstract:In high-conversion atom transfer radical polymerization (ATRP), all the reactions, such as radical termination, radical deactivation, dormant chain activation, monomer propagation, etc. could become diffusion controlled sooner or later, depending on relative diffusivities of the involved reacting species. These diffusion-controlled reactions directly affect the rate of polymerization and the control of polymer molecular weight. A model is developed to investigate the influence of diffusion-controlled reactions on the high conversion ATRP kinetics. Model simulation reveals that diffusion-controlled termination slightly increases the rate, but it is the diffusion-controlled deactivation that causes auto-acceleration in the rate ("gel effect") and loss of control. At high conversions, radical chains are "trapped" because of high molecular weight. However, radical centers can still migrate through (1) radical deactivation-activation cycles and (2) monomer propagation, which introduce "residual termination" reactions. It is found that the "residual termination" does not have much influence on the polymerization kinetics. The migration of radical centers through propagation can however facilitate catalytic deactivation of radicals, which improves the control of polymer molecular weight to some extent. Dormant chain activation and monomer propagation also become diffusion controlled and finally stop the polymerization when the system approaches its glass state. OPEN ACCESSPolymers 2015, 7 820

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“…Recent simulations [55] have shown that in ICAR ATRP the control over polymerization rate and polymer properties can be directly manipulated by adjusting the polymerization conditions. For instance, it was demonstrated that, depending on the ATRP catalyst reactivity, step-wise addition of conventional radical initiator in the ICAR ATRP of methyl methacrylate and styrene is needed to reach high conversion while still obtaining a good livingness and control over chain length with ppm levels of ATRP catalyst.…”

Section: Introductionmentioning

confidence: 99%

Computer‐Aided Optimization of Conditions for Fast and Controlled ICAR ATRP of n‐Butyl Acrylate

Porras

D’hooge

Reyniers

et al. 2013

Macro Theory & Simulations

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The potential of initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) for the synthesis of well‐defined poly(n‐butyl acrylate) is analyzed by means of simulations. The kinetic model accounts for reactivity differences between secondary and tertiary macrospecies and considers the possible influence of diffusional limitations. CuBr2 is used as transition metal salt and the commercially available N,N,N′,N″,N″‐pentamethyldiethylenetriamine as ligand. For targeted chain lengths (TCLs) up to 1000, the ICAR ATRP can be performed relatively quickly, and with ppm levels of ATRP catalyst. For moderate TCLs, slightly higher ppm levels are required if excellent control over chain length is also desired. In all cases, limited loss of end‐group functionality (EGF) results. magnified image

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Kinetic Modeling of ICAR ATRP

Cited by 83 publications

References 53 publications

Fed-Batch Control and Visualization of Monomer Sequences of Individual ICAR ATRP Gradient Copolymer Chains

Fed-Batch Control and Visualization of Monomer Sequences of Individual ICAR ATRP Gradient Copolymer Chains

Modeling the Influence of Diffusion-Controlled Reactions and Residual Termination and Deactivation on the Rate and Control of Bulk ATRP at High Conversions

Computer‐Aided Optimization of Conditions for Fast and Controlled ICAR ATRP of n‐Butyl Acrylate

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