Multi-trigger shape memory polymer nanocomposite

Shape memory polymers (SMPs) have a special functional ability to recover trained deformation upon a single trigger. This single trigger can be a hindrance in many applications where ambient conditions could cause accidental triggering. A means to regulate the possibility of accidental triggering would be by the addition of another trigger. The focus in this research was thus to investigate a means for a multiple trigger mechanism with a SMP nanocomposite. A commercially available shape memory polyurethane (SMPU) was filled with varying proportions (7.88 wt.%, 15.00 wt.%, and 21.29 wt.%) of magnetite nanoparticles and tested by thermomechanical methods, derived thermo-magnetic-mechanical methods, and shape memory methods. Current processing and testing provide results of an ability of the SMP nanocomposite to be controlled in shape deformation and recovery with both thermal and magnetic triggers. Furthermore, with the addition of the magnetite to the polymer matrix showed increases in material properties (i.e. tensile strength, modulus, and thermal conductivity) with proportional increase in magnetite filler content. Changes in basic shape memory properties (i.e. shape fixity and shape recovery) were seen to be minimal with the magnetite filler content and are slightly lower than the pure SMPU in accordance with the increasing amount of filler material. Overall, the produced SMP nanocomposite assumes to provide an interesting alternative to current SMPs with the ability to be triggered by both a thermal and magnetic field.