Synthesis and properties of novel UV – curable hyperbranched waterborne polyurethane/Fe3O4 nanocomposite films with excellent magnetic properties

A novel magnetic nanocomposite has been successfully synthesized by in situ polymerization method using the functionalized Fe3O4 nanoparticles as fillers and the hyperbranched waterborne polyurethane (HWPU) as matrix. The Fe3O4 nanoparticles prepared by solvothermal method were modified by vinyltriethoxysilane (VTEO) to improve the compatibility with HWPU, because the functionalized Fe3O4 nanoparticles could form effective crosslink points and combined with the HWPU by covalent bonds during the UV-curing process. The microstructure, morphology, emulsion stability, thermal behavior, gel content, mechanical properties, water resistance, solvent resistance and magnetic properties of nanocomposites have been characterized and investigated. It was found that the introduction of functionalized Fe3O4 contributed to the thermal stability, glass transition temperature, hardness and solvent resistance of the nanocomposites. What's more, the HWPU/Fe3O4 displayed excellent magnetic behavior, which would have a promising application in microwave-absorbing field.