To access infinitely recyclable plastics, one appealing approach is to design thermodynamically neutral systems based on dynamic covalent bond, the (de)polymerization of which can be easily manipulated with low energy cost. Here, we demonstrate the feasibility of this concept via the efficient synthesis of polythioesters PN^R-PenTE from penicillamine-derived β-thiolactones and their convenient depolymerization under mild conditions. The gem-dimethyl group adjusts the thermodynamics of (de)polymerization to near equilibrium, confers better (de)polymerization control by reducing the activity and conformational possibilities of the chain-end thiolate groups, and stabilizes the thioester linkages in the polymer backbone. PN^R-PenTE with tailored properties is conveniently accessible by altering the side chains. PN^R-PenTE can be recycled to pristine enantiopure β-thiolactones at >95% conversion from minutes to a few hours at room temperature. This work highlights the power of judicious molecular design and could greatly facilitate the development of a wide range of recyclable polymers with immense application potentials.

为了获得无限循环利用的塑料，一种吸引人的方法是设计基于动态共价键的热力学中性体系，该体系的（解聚）反应很容易以较低的能源成本进行操作。在这里，我们通过从青霉素胺衍生的β-硫代内酯高效合成多硫代酯PN ^R -PenTE以及在温和条件下方便地解聚证明了该概念的可行性。该宝石-二甲基组调节的（de）聚合的热力学至接近平衡，赋予更好的（de）通过降低活性和构象的可能性聚合控制链端硫醇基团，并稳定在聚合物主链上的硫酯键。PN ^R-PenTE具有定制的属性，可以通过更改侧链方便地进行访问。PN ^R -PenTE可以在室温下从数分钟到数小时以大于95％的转化率回收为原始的对映纯β-硫代内酯。这项工作突出了明智的分子设计的力量，并可能极大地促进具有巨大应用潜力的多种可回收聚合物的开发。