Hyperbranched polyurethane/Fe3O4 nanoparticles decorated multiwalled carbon nanotube thermosetting nanocomposites as microwave actuated shape memory materials

Hyperbranched polyurethane/Fe3O4 nanoparticles decorated multiwalled carbon nanotube (Fe3O4-MWCNT) nanocomposites were prepared by the in situ polymerization technique. The presence of Fe3O4 nanoparticles on the surface of the MWCNTs was confirmed by x-ray diffraction and transmission electron microscopic studies. The saturation magnetization value of Fe3O4-MWCNT was 0.23 emu/g. The glycidyl ether of bisphenol-A epoxy cured thermosetting nanocomposites exhibited enhanced tensile strength (6.4–38.5 MPa), scratch hardness (3.0–8.5 kg), and thermal stability (241–292 °C) with the increase of loading of Fe3O4-MWCNT (0–2 wt%). The nanocomposites possess good shape fixity over the repeated cycles of test. The nanocomposites also showed good shape recovery under the application of microwave irradiation. The shape recovery speed was found to be increased with the increase of the content of Fe3O4-MWCNT. Thus, the studied thermosetting nanocomposites have potential to be used as noncontact shape memory materials.