Reprocessing and reconfigurable shape recovery of epoxy and Fe3O4 nanocomposites enabled by crosslinking with a polymeric hardener bearing disulfide bonds

In this contribution, we reported the preparation of the nanocomposites of epoxy with Fe3O4 with poly(alpha-lipoic acid) (PLA) as a polymeric crosslinker. It was found that the surface reaction between Fe3O4 nanoparticles and the macromolecular crosslinker significantly facilitated the fine dispersion of the inorganic nanoparticles. In the meantime, dynamic disulfide bonds were successfully introduced into the nanocomposites. Therefore, the nanocomposites displayed the excellent reprocessing (recycling) properties. In addition, the nanocomposites had the shape memory properties; the original shapes of the shape memory nanocomposites can be reprogrammed via the exchange of dynamic disulfide bonds. Owing to the incorporation of Fe3O4 nanoparticles, the nanocomposites possessed the excellent paramagnetic and photothermal properties. Furthermore, the photothermal properties can be utilized to trigger the shape recovery in a non-contact fashion.