A Simplified Predictive Tool for Design and Analysis of SET-LRP Reactions with Mechanistic Insight,ACS Applied Polymer Materials

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A Simplified Predictive Tool for Design and Analysis of SET-LRP Reactions with Mechanistic Insight
ACS Applied Polymer Materials ( IF 4.4 ) Pub Date : 2020-10-28 , DOI: 10.1021/acsapm.0c00796
Kevin Gunter ₁ , Mirco Sorci ₁ , Georges Belfort ₁

Affiliation

Single-electron transfer (SET)-living radical polymerization (LRP) is a robust, fast, “green,” grafting method, similar but different from atom transfer radical polymerization, that operates at ambient temperature in the presence of oxygen and is industrially attractive. Solving a simplified reaction model with only five rather than 12 reactions in solution, for describing the SET-LRP scheme and verifying it with experimental data, we provide (i) a useful tool to predict conversion given initial conditions and rate constants, and (ii) key mechanistic insights with a parametric sensitivity analysis, illustrating the effects of initial conditions, kinetic rate constants, temperature, and copper particle size. Findings include: (i) Increasing the formation rate of radicals (i.e., k_act) exhibited a maximum in monomer conversion. (ii) The optimal ratio of initial conditions was found to be [MA]₀/[P_nX]₀/[Cu^IIX₂/L]₀ = 222/1/1.5, where [MA]₀ = 7.4 M. (iii) Increasing the temperature strongly improved monomer conversion with an inflection point. (iv) Using an order-of-magnitude and Damköhler number analysis, we provide a rationale for selecting small diameter particles and specify how they are likely to perform with SET-LRP reactions. Assumptions of the model include: Solid copper concentration was an infinite source of dissolved Cu^I and Cu^II and was available instantaneously (with Damköhler number ≪ 1, for reaction rather than diffusion limitation). Also, the reverse reaction of the disproportionation of Cu^I was negligible, polymer chain length did not affect reaction kinetics, and all intermediate reactions were neglected.

中文翻译：

具有机理见解的SET-LRP反应设计和分析的简化预测工具

单电子转移（SET）活性自由基聚合（LRP）是一种健壮，快速，“绿色”的接枝方法，与原子转移自由基聚合相似但不同，它在环境温度下，有氧条件下运行，具有工业吸引力。。为了描述SET-LRP方案并用实验数据进行验证，我们求解了一个简化的反应模型，该模型中只有5个反应而不是12个反应，我们提供了（i）在给定初始条件和速率常数的情况下预测转化的有用工具，以及（ii ）通过参数敏感性分析获得的重要机械洞察力，阐明了初始条件，动力学速率常数，温度和铜粒度的影响。研究结果包括：（i）增加自由基的形成率（即k_行为）在单体转化率方面显示出最大值。（ii）发现初始条件的最佳比率为[MA] ₀ / [P _n X] ₀ / [Cu ^II X ₂ / L] ₀ = 222/1 / 1.5，其中[MA] ₀ = 7.4M。（iii）提高温度极大地改善了具有拐点的单体转化率。（iv）使用量级和Damköhler数分析，我们提供了选择小直径粒子的原理，并指定了它们在SET-LRP反应中可能如何执行。该模型的假设包括：固铜浓度是溶解的Cu ^I和Cu ^II的无限来源并可以即时获得（Damköhler≪ 1，用于反应而不是扩散限制）。同样，Cu ^I歧化的逆反应可以忽略不计，聚合物链长不影响反应动力学，所有中间反应都可以忽略。

更新日期：2020-11-13

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