Crosslinked polyurethanes (PUs) with excellent mechanical properties have been widely used, but they cannot be reprocessed or recycled for the lack of chain mobility. Here, aluminum acetylacetonate (ALA) is used as the crosslinker to construct a novel crosslinked PU with dynamic bonds and coordinated linkages. This type of PU demonstrates two different recycling methods, including thermal remolding and solvent recycling. Due to the thermally reversible reaction between β-diketone and isocyanate, the crosslinked PU can be reprocessed under the thermal treatment. On the other hand, the coordinated linkage in the polyurethane can provide the solvent recycling ability based on the dissociation of the coordinated bonds of aluminum acetylacetonate in an acid solution. Furthermore, the solvent recycling method can be used to selectively separate and recycle the crosslinked PU from polymer blends, which provides a novel method for reusing and recycling the polymer blends. Furthermore, aluminum acetylacetonate can be directly applied in the existing widely used PU systems to achieve a good ecofriendly loop to recycle the PU. This research exhibits a simple and general method for creating tailorable crosslinked PU materials with superior recyclability.

中文翻译：

---

动态和配位化学相结合实现聚氨酯的双法回收

具有优异机械性能的交联聚氨酯 (PU) 已被广泛使用，但由于缺乏链流动性，它们无法再加工或回收。在这里，乙酰丙酮铝 (ALA) 用作交联剂，以构建具有动态键和配位键的新型交联 PU。这种类型的 PU 展示了两种不同的回收方法，包括热重塑和溶剂回收。由于β-二酮与异氰酸酯之间的热可逆反应，交联后的聚氨酯可以在热处理下进行再加工。另一方面，聚氨酯中的配位键可以提供基于乙酰丙酮铝配位键在酸溶液中解离的溶剂回收能力。此外，该溶剂回收法可用于从聚合物共混物中选择性地分离和回收交联PU，为聚合物共混物的再利用和回收提供了一种新方法。此外，乙酰丙酮铝可以直接应用于现有广泛使用的聚氨酯系统，以实现良好的生态友好循环来回收聚氨酯。本研究展示了一种简单通用的方法，用于创建具有卓越可回收性的可定制交联 PU 材料。