Dynamic covalent chains that composed of three or five dynamic polyurea bonds are introduced into cross-linked polyurethane to overcome the classical dilemma between healing rate and thermo-mechanical properties. Comparing with dynamic urea bond, the incorporation of the dynamic polyurea chains with multiple leads to significantly improved thermo-mechanical performance and healing rate/efficiency on the network. Remarkably, several folds' increases in tensile and adhesion shear strength as well as 53 °C enhancement in glass transition temperature are achieved without sacrificing the material properties of the polyurethane network. We attribute the improvements to the decomposed polyurea chain segments, which have higher diffusivity and larger quantity than the dynamic urea bond that tied in the control network. This study provides a concept of dynamic covalent chain to address the classical dilemma between healing performances and thermo-mechanical properties among healable thermosets.

由三个或五个动态聚脲键组成的动态共价链被引入到交联聚氨酯中，以克服愈合速度和热机械性能之间的经典难题。与动态尿素键相比，动态聚脲链与多种结合可以显着改善网络的热机械性能和治愈率/效率。值得注意的是，在不牺牲聚氨酯网络材料性能的情况下，拉伸强度和粘合剪切强度提高了几倍，玻璃化转变温度提高了53°C。我们将这些改进归因于可分解的聚脲链段，该链段的扩散率和数量均比控制网络中的动态尿素键高。