Rate enhancement of nitroxide-mediated living free-radical polymerization by continuous addition of initiator

He, Junpo; Chen, Jingmin; Li, Li; Pan, Jingyun; Li, Chengming; Cao, Jizhuang; Tao, Yudong; Hua, Fengjun; Yang, Yuliang; McKee, G. E.; Brinkmann, Susanne

doi:10.1016/s0032-3861(99)00689-8

Cited by 23 publications

(13 citation statements)

References 25 publications

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“…This may have important practical implications for the control of the polymerization rate as, for a given value of K, there is no point in adding initiator if the lower bound of the rate is not exceeded. Our group and others [33,34] have found that some sequences of initiator addition in TEMPO mediated styrene polymerization can increase dramatically the reaction rate, still keeping reasonably low polydispersities. This is attributed to a compensation of the persistent radical effect by the extra initiator added.…”

Section: Consequences Of the Analysis For Rigorous Nqementioning

confidence: 74%

On the Nitroxide Quasi‐Equilibrium in the Alkoxyamine‐Mediated Radical Polymerization of Styrene

Saldívar‐Guerra

Bonilla

Becerril

et al. 2006

Macro Theory & Simulations

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Summary: The range of validity of two popular versions of the nitroxide quasi‐equilibrium (NQE) approximation used in the theory of kinetics of alkoxyamine mediated styrene polymerization, are systematically tested by simulation comparing the approximate and exact solutions of the equations describing the system. The validity of the different versions of the NQE approximation is analyzed in terms of the relative magnitude of (dN/dt)/(dP/dt). The approximation with a rigorous NQE, kc[P][N] = kd[PN], where P, N and PN are living, nitroxide radicals and dormant species respectively, with kinetic constants kc and kd, is found valid only for small values of the equilibrium constant K (10−11–10−12 mol · L−1) and its validity is found to depend strongly of the value of K. On the other hand, the relaxed NQE approximation of Fischer and Fukuda, kc[P][N] = kd[PN]0 was found to be remarkably good up to values of K around 10−8 mol · L−1. This upper bound is numerically found to be 2–3 orders of magnitude smaller than the theoretical one given by Fischer. The relaxed NQE is a better one due to the fact that it never completely neglects dN/dt. It is found that the difference between these approximations lies essentially in the number of significant figures taken for the approximation; still this subtle difference results in dramatic changes in the predicted course of the reaction. Some results confirm previous findings, but a deeper understanding of the physico‐chemical phenomena and their mathematical representation and another viewpoint of the theory is offered. Additionally, experiments and simulations indicate that polymerization rate data alone are not reliable to estimate the value of K, as recently suggested.Validity of the rigorous nitroxide quasi‐equilibrium assumption as a function of the nitroxide equilibrium constant.imageValidity of the rigorous nitroxide quasi‐equilibrium assumption as a function of the nitroxide equilibrium constant.

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Section: Consequences Of the Analysis For Rigorous Nqementioning

confidence: 74%

On the Nitroxide Quasi‐Equilibrium in the Alkoxyamine‐Mediated Radical Polymerization of Styrene

Saldívar‐Guerra

Bonilla

Becerril

et al. 2006

Macro Theory & Simulations

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“…Alternatively, several groups have enhanced polymerization rates by the continuous addition of radical initiators to consume excess nitroScheme 8 Scheme 7 xide. [153][154][155][156][157] The organic acid salt 2-fluoro-1-methylpyridinium p-toluenesulfonate has been used to trap the mediating nitroxide as its oxammonium salt 47 and hydroxylamine anion salt 48 in much the same way as a Brønsted acid. 158,159 The addition of acetic anhydride has also been shown to increase TEMPO-mediated radical polymerization rates.…”

Section: Scheme 4 Schemementioning

confidence: 99%

Nitroxide decomposition: Implications toward nitroxide design for applications in living free‐radical polymerization

Nilsen

Braslau

2005

J. Polym. Sci. A Polym. Chem.

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ABSTRACT:Nitroxides bearing an a-hydrogen decompose upon heating in a bimolecular reaction. A new mechanism is proposed for the decomposition of t-butylisopropylphenyl nitroxide (TIPNO) involving the formation of a head-to-tail dimer, single electron transfer to form an oxammonium salt, epimerization to the corresponding nitrone, and elimination to form a conjugated oxime. This mechanism may provide insights into designing new nitroxides for use in controlled polymerization.

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“…, the use of conventional radical initiators with a long half-life time [46], the continuous addition of conventional radical initiator [47], and rate-enhancing organic acids [48].…”

Section: Introductionmentioning

confidence: 99%

Exploring the Full Potential of Reversible Deactivation Radical Polymerization Using Pareto-Optimal Fronts

et al. 2015

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Abstract:The use of Pareto-optimal fronts to evaluate the full potential of reversible deactivation radical polymerization (RDRP) using multi-objective optimization (MOO) is illustrated for the first time. Pareto-optimal fronts are identified for activator regenerated electron transfer atom transfer radical polymerization (ARGET ATRP) of butyl methacrylate and nitroxide mediated polymerization (NMP) of styrene. All kinetic and diffusion parameters are literature based and a variety of optimization paths, such as temperature and fed-batch addition programs, are considered. It is shown that improvements in the control over the RDRP characteristics are possible beyond the capabilities of batch or isothermal RDRP conditions. Via these MOO-predicted non-classical polymerization procedures, a significant increase of the degree of microstructural control can be obtained with a limited penalty on the polymerization time; specifically, if a simultaneous variation of various polymerization conditions is considered. The improvements are explained based on the relative importance of the key reaction rates as a function of conversion. OPEN ACCESSPolymers 2015, 7 656

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Rate enhancement of nitroxide-mediated living free-radical polymerization by continuous addition of initiator

Cited by 23 publications

References 25 publications

On the Nitroxide Quasi‐Equilibrium in the Alkoxyamine‐Mediated Radical Polymerization of Styrene

On the Nitroxide Quasi‐Equilibrium in the Alkoxyamine‐Mediated Radical Polymerization of Styrene

Nitroxide decomposition: Implications toward nitroxide design for applications in living free‐radical polymerization

Exploring the Full Potential of Reversible Deactivation Radical Polymerization Using Pareto-Optimal Fronts

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