Recognizing the importance of good phase separation for high-quality strain fixing in thermoplastic
polyurethanes, Chen et al. (17) studied the addition of low-molecular-weight additives
and end-cappers to common polyester diol-based thermoplastic polyurethanes (TPUs), including
those based on poly(1,4-butylene adipate) and poly(hexamethylene adipate). Strain fixing improved
by 20% upon end-capping such TPUs with octadecanol (HO-C18H37). Employing a different approach
to the same end, Meng & Hu (18) and Ji et al. (19) studied the impact of heat treating
SMP fibers of poly(-caprolactone) (PCL)-based and poly(ethylene adipate)-based polyurethanes,
respectively. In both cases, significant improvements in fixing but small impacts on recovery were
witnessed. Future work should involve similar studies on polyurethanes with substantially lower
hard-segment contents because this will engender higher elasticity and concomitant elastic strain
fixing and recovery.We expect that improvements in SMP textiles will lead to diverse applications
ranging from wound care to fabrics.