Nanocomposites of polyhydroxyurethane with Fe₃O₄ nanoparticles: Synthesis, shape memory and photothermal properties

Abstract

Abstract The nanocomposites of ferroferric oxide (Fe 3 O 4 ) with polyhydroxyurethane (PHU) were fabricated via a physical mixing approach. This process involved grafting poly( N ‐vinyl pyrrolidone) (PVPy) chains onto the surfaces of Fe 3 O 4 nanoparticles via surface‐initiated living radical polymerization. The PVPy‐grafted Fe 3 O 4 nanoparticles were directly incorporated into the precursors of PHUs [i.e., bis(cyclic carbonate) and a trifunctional amine] and the mixtures were cured at high temperatures to form organic–inorganic composites. This method ensured that Fe 3 O 4 nanoparticles were finely dispersed within the PHU matrix through the strong intermolecular hydrogen bonding between PVPy and PHU. Compared to plain PHU network, the nanocomposites had enhanced thermomechanical properties, including higher glass transition temperatures ( T g 's) and improved tensile mechanical properties. The inclusion of Fe 3 O 4 nanoparticles also enhanced the shape memory properties of the PHU networks, improving shape recovery rates, fixity of transient shapes, and recovery of the original shapes. In addition, the nanocomposites demonstrated paramagnetic and photothermal properties and the photothermal behavior enabled a non‐contact control of shape recovery. Highlights Poly(N‐vinyl pyrrolidone)‐grafted Fe 3 O 4 nanoparticles were synthesized. Nanocomposites of PHU with Fe 3 O 4 were prepared via a physical blending approach. Incorporation of Fe 3 O 4 resulted in improved thermomechanical properties. The nanocomposites had the photothermal properties.