An experimental-numerical study on shape memory behavior of PU/PCL/ZnO ternary blend

摘要

Shape memory polymer composites have attracted significant attention due to novel properties and great applications. In this article, we focus on the fabrication and simulation of polyurethane/polycaprolactone nanocomposites. The polyurethane/polycaprolactone blends containing ZnO nanoparticles (5 to 30 wt%) are fabricated using a solution mixing and casting method. It is found that significant improvement of polyurethane/polycaprolactone composites in Young's modulus is achieved by incorporating 20 wt% of ZnO nanoparticles; also, the results of the shape recovery ratio reveal that adding an optimum amount of ZnO (the reinforcement) can increase the shape recovery ratio (for 20 wt% of ZnO). These results could most likely be explained by the fact that some particles restrict the hard segment-soft segment interactions and provide more mobility to polycaprolactone components, while the other nanoparticles can act as the nucleating agent for polycaprolactone chains. A generalized Maxwell model is then used to examine the shape memory behavior of shape memory polymer composites. The dynamic mechanical thermal analysis results are utilized to define the model coefficients and the simulation is carried out to determine the shape recovery ratio. Simulation of this shape recovery ratio for shape memory polymer composites reveals that the numerical results are in good agreement with those of the experimental data.