Mechanical Properties of Shape-Memory Polymers, Polymer Blends, and Composites

Abstract

Shape-memory polymers (SMPs) are widely employed in aerospace, biomedical, portable electronic devices, etc., where their multiple-shape capabilities are considered. In order to avoid the failure of the SMPs before shape change, it is critical to possess excellent mechanical properties along with their inherent shape-memory ability. Recent research reports highlight the importance of SMPs with high strength and toughness. Conventional mechanical testing procedures such as tensile, bending, and fracture toughness are used to outline the static mechanical performance of SMPs. The cyclic mechanical testing facilitates the evaluation of shape-memory parameters such as shape fixity (R_f) and shape recovery (R_r) ratio. In a recent development, nanoindentation technique is used to probe the shape-memory process at nanolevel. SMPs based on epoxy, polyurethane, PCL, etc., were investigated for their both static and cyclic mechanical performance. Well-balanced mechanical and shape-memory performance can be tailored in SMPs by careful tuning of crystallinity, cross-link density, and fiber/filler reinforcement.