Shape memory polyurethane nanocomposites with a functionalized graphene

The roles of graphene in shape memory polyurethane nanocomposite (SMPUN) as a reinforcing filler, as a fixed structure for memorizing a specified original shape, and as a conductive filler to actuate shape recovery by resistive heating, were examined. The effectiveness of each role was modulated by functionalizing graphene with a hydroxyl group through oxidation with H₂O₂. The reinforcing effect of graphene and its role as a fixed structure were enhanced by the hydroxyl groups due to the increased grafting of polyurethane chains on graphene during the in situ preparation of SMPUN. However, the oxidation reduced the conductivity of SMPUN, resulting in the deterioration of resistive heating.