Shape-Memory Polymers Containing Aramid Hard Segments and Polycaprolactone Soft Segments

摘要

When a shape-memory material is deformed into a temporary shape, it will release the elastic energy stored during the initial deformation and relax to its original stress-free conformation only when heated above a certain recovery temperature. Shape-memory alloys, such as nickel-titanium alloy (nitinol), are among the most studied shape-memory materials, and their applications range from stents, flexible spectacle frames to actuated devices. However, a major drawback of shape-memory alloys is their high cost and limited maximum strains (≤8%). Shape-memory polymers (SMPs) provide an attractive alternative since they are cheaper to make and process. In addition, SMPs are generally able to withstand much higher elongations up to several hundred percent, although this depends on the flexible segments chosen.