Magnetically-sensitive shape memory polyurethane composites crosslinked with multi-walled carbon nanotubes

Magnetically-sensitive polyurethane composites, which were crosslinked with multi-walled carbon nanotubes (MWCNTs) and were filled with Fe3O4 nanoparticles, were synthesized via in situ polymerization method. MWCNTs pretreated with nitric acid were used as crosslinking agents. Because of the crosslinking of MWCNTs with polyurethane prepolymer, the properties of the composites with a high content of Fe3O4 nanoparticles, especially the mechanical properties, were significantly improved. The composites showed excellent shape memory properties in both 45 degrees C hot water and an alternating magnetic field (f = 45 kHz, H = 29.7 kA m(-1)). The shape recovery time was less than one minute and the shape recovery rate was over 95% in the alternating magnetic field. (C) 2013 Elsevier Ltd. All rights reserved.