Grafting photosensitive polyurethane onto colloidal silica for use in UV-curing polyurethane nanocomposites

A photosensitive polyurethane was grafted onto the surface of silica particles using amine-isocyanate coupling reactions. The grafted PU chains enhanced the silica-PUA interfacial interaction and improved their compatibility, and this allowed a homogeneous dispersion of the small PU-silica clusters in the PUA matrix. The PU-silica nanoparticles functioned effectively as multifunctional cross-linkers as well as reinforcing fillers and significantly enhanced the Young's modulus, tensile strength, and thermal stability of PUA nanocomposites.