Shape-Memory Polyurethane Polymers

Polyurethanes (PUs) are one of the most widely used polymers in research and industry. They can be synthesized from chemical sources and natural sources. PUs are a very useful class of polymers and exhibit many desirable properties that can be exploited in various applications. PUs are formed by the reaction between polyols and isocyanates. A wide variety of polyols and isocyanates are available for synthesis, and hence we can produce a large number of PUs. PUs show high mechanical strength, chemical resistance, flexibility, and resilience. One of the major advantages of some specially designed PUs is their ability to recover their primary shape, which is known as shape memory. The shape-memory effect (SME) of PUs makes them popular in biomedical, electronic, and thermal applications. The SME can be monitored using different measures such as shape fixity, recovery time, and recovery rate. Various stimuli are applied to shape-memory materials to induce shape memory. PU polymers can be modified with different nanofillers, and these fillers influence the shape-recovery parameters. PU composites are popular because of a good property-price relationship. This chapter discusses the various factors affecting the SME of PU composites and the effect of different types of fillers on the PU matrix.