Effect of the blend ratio on the shape memory and self-healing behaviour of ionomer-polycyclooctene crosslinked polymer blends

Abstract

This work reports on the development of a novel polymer blend with thermally triggered shape memory and self-healing properties. Blends were prepared by mixing a self-healing ionomer (Surlyn 9520) and polycyclooctene (with and without crosslinking agent) in different ratios. The regions of thermal activation were determined by thermogravimetric analysis, differential scanning calorimetry and oscillatory shear rheology. Consecutively, the shape memory and self-healing behaviour were investigated by a torsion procedure and tensile testing respectively. It was found that ionomer/crosslinked polycyclooctene blends of 70/30 wt% lead to polymers showing partial macroscopic healing and repeatable shape memory characteristics. The new polymer system shows both dual and triple shape memory behaviour and a near to 100% stiffness recovery after healing of crosscuts at standard ionomer healing conditions. Furthermore, the relation between terminal relaxation and self-healing in blends is shown. This study introduces a triple shape memory polymer with self-healing properties by a blending strategy thereby clearing the path for more durable materials based on shape memory properties.