Thermo-driven self-healable organic/inorganic nanohybrid polyurethane film with excellent mechanical properties

Waterborne polyurethane (WPU) is widely applied in many fields; however, it is limited by its drawback of low mechanical strength and short lifespan. Polymer nanocomposites have been developed for many years to enhance the mechanical behavior of materials. Nevertheless, obtaining nanofillers with even dispersion to obtain improved mechanical performance is difficult. To solve the above problems, silica nanoparticles modified by furfuryl (furan@SiO 2 ) were synthesized according to the sol–gel process. By introducing furan@SiO 2 into a maleimide-terminated waterborne polyurethane matrix, a self-healing system was constructed through a DA/retro-DA process among furan groups and maleimide-terminated waterborne polyurethane, and a series of WPU films with different furan@SiO 2 (WMPUS-x) contents were prepared. The structure of furan@SiO 2 was clearly corroborated by TEM, SEM, FTIR, etc. Moreover, confirmed by tensile tests, the mechanical properties of all WPU samples were significantly improved due to the addition of rigid furan@SiO 2 , and their first self-healing efficiencies were all higher than 88%.