Huge annual consumption of thermoplastics results in the generation of large amounts of waste after their service life. Currently, the most popular recycling method based on mechanically melt‐reprocessing deteriorates the material performance and is economically unattractive, which makes it unviable to be implemented in large scale. Herein, we present a chemical upcycling strategy that can transform dimethylglyoxime‐urethane based thermoplastic waste into thermoset product with superior mechanical properties and higher economic values than the initial one. It is found that the dimethylglyoxime‐urethane moiety has dynamic nature, endowing the material with open‐loop upcycling ability. By removing the dimethylglyoxime segment via a simple sublimation process, the material structure is transformed from linear molecular into crosslinked network. More interestingly, the transformation is reversible, and the regenerated crosslinked network can be transformed back to linear molecule by returning the removed dimethylglyoxime segment to the material, which means the upcycled product can be recycled again after its service life. Our linear/crosslinked transformation strategy provide a new option for recycling thermoplastic waste.

中文翻译：

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基于动态二甲基乙二肟-氨基甲酸酯部分的热塑性塑料化学升级回收为热固性塑料


热塑性塑料的年消耗量巨大，导致其使用寿命后会产生大量废物。目前，最流行的基于机械熔融再加工的回收方法会恶化材料性能，并且在经济上没有吸引力，这使得它无法大规模实施。在此，我们提出了一种化学升级回收策略，可以将基于二甲基乙二肟-氨基甲酸酯的热塑性废物转化为比最初的热固性产品具有优越的机械性能和更高的经济价值的热固性产品。研究发现，二甲基乙二肟-氨基甲酸酯部分具有动态性质，赋予材料开环升级回收能力。通过简单的升华过程去除二甲基乙二肟链段，材料结构从线性分子转变为交联网络。更有趣的是，这种转化是可逆的，通过将去除的二甲基乙二肟链段返回材料，可以将再生的交联网络转化回线性分子，这意味着升级回收的产品可以在其使用寿命后再次回收。我们的线性/交联转化策略为回收热塑性废料提供了新的选择。