An iron-based electrochemically mediated atom transfer radical polymerization (eATRP) system with tunable catalytic activity was developed by adjusting the supporting electrolyte formula. Kinetic behaviors of the systems using four typical supporting electrolytes (namely, TBABr, TBAPF₆, TBACl, and TBABF₄) were investigated. The type of anions was found to significantly affect the polymerization kinetics. TBAPF₆ system proceeded with a considerable polymerization rate, whereas TBABr system showed better controllability. Importantly, the effect of supporting electrolyte on eATRP kinetics (mainly on ATRP equilibrium) was confirmed through kinetic modeling. Furthermore, the effect of catalyst loading using TBAPF₆ as supporting electrolyte was also studied, and the results showed an uncontrolled polymerization for catalyst loading lower than 500 ppm. When hybrid supporting electrolyte (TBAPF₆/TBABr) was used to tune catalytic activity, the polymerization slows down and the dispersity decreases with the increase in TBABr ratio. Polymers with a narrow molecular weight distribution (dispersity index <1.5) were obtained using 100% TBABr under 100 ppm catalyst. Besides, experimental attempt to improve the controllability by adding halogen donors was made, whereas the halogen donors just prolonged the induction period and no improvement was achieved. As a whole, a deeper understanding of kinetic studies is obtained by these controlled trials. © 2017 American Institute of Chemical Engineers AIChE J, 2017

中文翻译：

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具有可调催化活性的铁基电化学介导的原子转移自由基聚合

通过调整支持电解质的配方，开发了具有可调催化活性的铁基电化学介导原子转移自由基聚合（eATRP）系统。研究了使用四种典型支持电解质（即TBABr，TBAPF ₆，TBAC1和TBABF ₄）的系统的动力学行为。发现阴离子的类型显着影响聚合动力学。TBAPF ₆系统以可观的聚合速率进行，而TBABr系统显示出更好的可控制性。重要的是，通过动力学模型证实了支持电解质对eATRP动力学的影响（主要是对ATRP平衡的影响）。此外，使用TBAPF ₆的催化剂负载量的影响还研究了作为载体电解质的催化剂，结果表明，对于低于500 ppm的催化剂载量，聚合不受控制。当使用混合支持电解质（TBAPF ₆ / TBABr）调节催化活性时，聚合反应变慢，并且分散度随着TBABr比的增加而降低。在100 ppm催化剂下使用100％TBABr，可获得分子量分布窄（分散指数<1.5）的聚合物。此外，进行了通过添加卤素供体来改善可控性的实验尝试，而卤素供体仅延长了诱导期，没有得到改善。总体而言，这些对照试验对动力学研究有了更深入的了解。©2017美国化学工程师学会AIChE J，2017