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首页> 外文期刊>Journal of Materials Chemistry, A. Materials for energy and sustainability >Dynamic covalent urea bonds and their potential for development of self-healing polymer materials
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Dynamic covalent urea bonds and their potential for development of self-healing polymer materials

机译：动态共价尿素键及其开发自愈聚合物材料的潜力

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Self-healing polymer materials have drawn rapidly increasing interest over the last decade, and have been studied and used in an ever-increasing range of applications. Herein, we successfully make the covalent urea bond - a pinnacle of stability due to strong resonance effects - dynamic in nature through mediation of zinc salts. The dynamic covalent character of urea in the presence of zinc ions is confirmed through dissociation reaction experiments and quantum chemical calculations of small-molecule model urea compounds. In line with our experiments, the modelling results suggest that the presence of zinc ions speeds up the reaction of urea dissociation by two orders of magnitude via the formation of O-bound Zn complexes. Based on such dynamic covalent urea bonds, we then develop a novel class of self-healing polymer materials with excellent healing efficiencies. Different kinds of self-healing and reprocessable polyurea materials were prepared, with polymer properties that can be easily tuned by varying the degree of crosslinking and the molecular weight of the siloxane precursor. Since different kinds of self-healing polyurea materials could easily be prepared due to the commercial availability of a very wide range of amine and isocyanate monomers, this introduction of self-healing properties is expected to have significant potential in a range of applications, such as coatings, paints, and 3D printing. In addition, this introduces polyureas and other urea-containing polymers as a class of highly stable, yet easily reprocessable plastics, which is highly relevant given the globally desired more sustainable use of plastics.
机译：在过去十年中，自我愈合的聚合物材料令人迅速增加利息，并已经在不断增加的应用范围内进行了研究。在此，我们成功地制备了共价尿素键 - 由于强烈的共振效应导致的稳定性稳定性 - 通过锌盐的调解动态。通过解离反应实验和小分子模型尿素化合物的量子化学计算来证实锌离子存在下尿素的动态共价特征。符合我们的实验，造型结果表明，锌离子的存在通过形成O-结合的Zn络合物的形成，尿素离解的反应加速了尿素离解的反应。基于这种动态的共价尿素键，我们开发了一种具有优异的愈合效率的新型自我愈合聚合物材料。制备不同种类的自愈和再加工的聚脲材料，通过改变交联度和硅氧烷前体的分子量，可以容易地调节聚合物性质。由于由于胺类和异氰酸酯单体的商业可用性，因此可以容易地制备不同种类的自愈性聚脲材料，因此这种自我愈合性能的引入预计在一系列应用中具有显着潜力，例如涂料，涂料和3D打印。此外，这引入了含有含有尿素和其他尿素的聚合物，作为一类高度稳定的，但易于再加工的塑料，这对全球所需的塑料更可持续使用具有高度相关性。

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