Synthesis and characterization of novel covalently linked waterborne polyurethane/Fe3O4 nanocomposite films with superior magnetic, conductive properties and high latex storage stability

Abstract Environmentally friendly novel conductive, magnetic films derived from waterborne polyurethane (WPU) and Fe 3 O 4 were successfully synthesized by in situ polymerization technique. Fe 3 O 4 nanoparticles prepared via a solvothermal method were covalently functionalized with 3-(triethoxysilyl) propyl isocyanate (IPTS) to improve dispersion and compatibility with the WPU matrix. Different from previous work, the modified Fe 3 O 4 nanoparticles (Fe 3 O 4 -IPTS) can chemically bond with WPU chains and form stable nanocomposite latexes before UV-curing, which benefited the improvement in some performances of WPU. The results revealed that the functionalization of Fe 3 O 4 facilitated the dispersion of Fe 3 O 4 as fillers in the WPU matrix and greatly improved the storage stability of the WPU/Fe 3 O 4 nanocomposite latex (>3 months). Furthermore, the solvent resistance, mechanical properties, electrical conductivity, and magnetic properties of WPU were enhanced with incorporation of Fe 3 O 4 -IPTS. Importantly, the nanocomposites showed high electrical conductivity (8.43 × 10 −4  S/cm) and superior magnetic properties (14.22 emu/cm 3 ) with a low Fe 3 O 4 -IPTS content of 8.0 wt.%, providing a promising route to prepare environmentally friendly WPU-based microwave absorption materials.