The ring opening copolymerization of trimethylene carbonate (TMC) and dithiolane trimethylene carbonate (DTC) using acidic and basic organocatalysts, i.e., diphenyl phosphate (DPP) and triazabicyclo[4.4.0]dec-5-ene (TBD), was systemically investigated. Interestingly, DPP and TBD gave rise to completely different polymerization kinetics and copolymer sequences. The copolymerization of TMC and DTC using methoxy poly(ethylene glycol) (mPEG–OH) as an initiator and DPP as a catalyst proceeded in a first-order manner and to near completion in 72 h for both monomers, yielding well-controlled copolymers with random sequences, predictable molar mass, and low dispersity (M_w/M_n = 1.09–1.19). By contrast, TBD brought about much faster copolymerization of TMC and DTC under similar conditions (high monomer conversion achieved in 2–4 h), to furnish copolymers with controlled molar mass and moderate dispersity (M_w/M_n = 1.27–1.80). Moreover, polymerization kinetics revealed that DTC was preferentially polymerized followed by first-order polymerization of TMC, leading to blocky copolymers. These results signify that type of organocatalysts has a critical influence on polymerization kinetics of cyclic carbonates, copolymer sequence, and molar mass control.

中文翻译：

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碳酸三亚甲基酯和二硫杂环戊烷碳酸三亚甲基酯的有机催化开环共聚合：有机催化剂对共聚动力学和共聚物微结构的影响

系统地研究了使用酸性和碱性有机催化剂，即磷酸二苯酯（DPP）和三氮杂双环[4.4.0]癸-5-烯（TBD），对碳酸亚丙酯（TMC）和碳酸二硫杂环戊烷三亚甲基酯（DTC）进行开环共聚。有趣的是，DPP和TBD引起了完全不同的聚合动力学和共聚物序列。使用甲氧基聚乙二醇（mPEG-OH）作为引发剂和DPP作为催化剂，TMC和DTC的共聚以一种一级方式进行，并且两种单体均在72小时内接近完成，从而得到具有良好控制的共聚物。随机序列，可预测的摩尔质量和低分散性（M _w / M _n= 1.09–1.19）。相比之下，TBD在相似的条件下（2-4小时内实现了高单体转化率）使TMC和DTC的共聚速度更快，从而提供了具有可控的摩尔质量和中等分散度的共聚物（M _w / M _n = 1.27-1.80）。此外，聚合动力学表明，DTC先被聚合，然后再进行TMC的一级聚合，从而形成嵌段共聚物。这些结果表明，有机催化剂的类型对环状碳酸酯的聚合动力学，共聚物序列和摩尔质量控制具有至关重要的影响。