A guanidine–zinc catalyst, which was nontoxic and highly active in the ring-opening polymerization (ROP) of polylactide (PLA) under industrial conditions, was assessed for its performance in the alcoholysis and aminolysis of PLA under mild conditions. Both techniques exhibited high conversion and yield in chemical recycling of PLA into value-added molecules, such as alkyl lactate and hydroxypropanamide derivatives, respectively. Notably, aminolysis was found to be significantly more efficient than alcoholysis, allowing >99% PLA conversion in less than 1 h and even selective degradation of commercialized PLA products in less than 2 h (>99% conversion). Additionally, the unprecedented approach employing diols and diamines as nucleophiles has been utilized to synthesize new, repolymerizable diol monomers, which upon reaction with dicarboxylic acids yield controllable poly(ester–amide) (PEA) structures with tunable T_g values ranging from 12.8 to 117.6 °C. We have developed efficient solutions for alcoholysis and aminolysis of polyesters and have successfully created a technological process to transform PLA from “old” to “new”.

中文翻译：

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用于 PLA 废物化学升级回收的锌催化剂：聚（酯-酰胺）的新型工业单体资源


胍锌催化剂在工业条件下聚丙交酯（PLA）的开环聚合（ROP）中无毒且具有高活性，评估了其在温和条件下PLA醇解和氨解中的性能。这两种技术在将 PLA 化学回收成增值分子（例如乳酸烷基酯和羟基丙酰胺衍生物）时均表现出高转化率和产率。值得注意的是，氨解比醇解效率明显更高，可以在不到 1 小时内实现 >99% 的 PLA 转化，甚至可以在不到 2 小时内选择性降解商业化的 PLA 产品（>99% 转化）。此外，采用二醇和二胺作为亲核试剂的前所未有的方法已被用来合成新的、可再聚合的二醇单体，其与二羧酸反应后产生具有可调T _g 的可控聚（酯-酰胺）（PEA）结构值范围为 12.8 至 117.6 °C。我们开发了高效的聚酯醇解、氨解解决方案，并成功打造了PLA“旧”向“新”转变的工艺流程。