3D printing of soft actuators in nano-filled shape memory thermoplastic polyurethane

Today new horizons have opened thanks to the integration of additive manufacturing and shape memory polymers (SMP). Additive manufacturing by fused deposition modelling (FDM) is used to develop new concept soft robotics with SMP. A thermoplastic polyurethane SMP for biomedical uses has been modified by aluminum nanoparticles and multi-walled carbon nanotubes to produce an innovative SMP. The new composite has been extruded to produce the 3D printing wire, which has been used to print a three-dimensional structure. The SM behavior of the composite has been investigated by calorimetry and recovery properties. For comparison the same studies have been carried out to pristine thermoplastic polyurethane. Differential scanning calorimetry, shape fixity and shape recovery ratios, recovery time and recovery force have been investigated for 3D printed structures of pristine and composite samples. The composite demonstrated better results in terms of recovery properties with respect to the pristine material. For this reason, the composite can be a good candidate for soft robotics applications.