B–O bonds are effective for constructing self-healing polymers, because of their unique combination of high thermodynamic stability and kinetic tunability. However, it is still challenging to develop boron-containing polymers that show simultaneously high mechanical strength, good hydrolytic stability, and autonomous self-healing ability. Herein, we designed and synthesized a phenol compound with three hydroxyls, two of which form boronic ester with boronic acid while the other one can promote the dynamic exchange of B–O bonds. Taking advantage of the new boronic esters as the cross-linking sites, a series of strong and tough elastomers with outstanding self-healing capacities at room temperature were successfully fabricated. The new design concept provides a novel type of dynamic covalent boronic esters as the platform for synthesizing durable and functional self-healing materials. Moreover, phenol compounds with three hydroxyl groups are abundant in the natural product, tannic acid (TA), which can also form dynamic boronic esters with boronic acid and be used to derive polymers with excellent recyclability. Therefore, this new system might facilitate the commercialization of boron-based dynamic covalent polymers as viable alternatives to contemporary commodity thermosets.

中文翻译：

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通过促进具有相邻羟基的硼酸酯中的键交换而实现的坚韧和自愈聚合物

B-O 键可有效构建自修复聚合物，因为它们具有高热力学稳定性和动力学可调性的独特组合。然而，开发同时具有高机械强度、良好水解稳定性和自主自修复能力的含硼聚合物仍然具有挑战性。在此，我们设计并合成了一种具有三个羟基的酚类化合物，其中两个羟基与硼酸形成硼酸酯，另一个可以促进 B-O 键的动态交换。利用新型硼酸酯作为交联位点，成功制备了一系列具有优异室温自修复能力的强韧弹性体。新的设计理念提供了一种新型的动态共价硼酸酯作为合成耐用和功能性自修复材料的平台。此外，具有三个羟基的酚类化合物在天然产物单宁酸（TA）中含量丰富，还可以与硼酸形成动态硼酸酯，用于衍生具有优异可回收性的聚合物。因此，这种新系统可能会促进基于硼的动态共价聚合物作为当代商品热固性塑料的可行替代品的商业化。