Facile approach for imparting shape memory behavior to traditional thermoplastic polyurethane via interaction between different hard segments

Abstract The stability of hard domain is a key factor affecting the shape memory properties of thermoplastic polyurethane (TPU). However, the physical interaction in hard domains is weak for most kinds of TPU, leading to a plastic deformation and thus significantly decreasing the shape recovery ratio of TPU. In this work, a new strategy for constructing shape memory TPU was proposed, and the blends was prepared by simple solution mixing based on IPDI‐PU and HDI‐PU, in which isophorone diisocyanate (IPDI) with alicyclic structure was introduced in hard segments of IPDI‐PU, and hexamethylene diisocyanate (HDI) with linear structure was introduced in hard segments of HDI‐PU. With the introduction of HDI‐PU into IPDI‐PU, hydrogen bonds between mixed hard domains were formed more easily, which made it possible to tailor the stability of hard domains in PU blends by changing the composition of IPDI‐PU and HDI‐PU. Shape memory behavior of IPDI‐PU was difficult to be observed, while the shape fixity ratio and recovery ratio of the blends containing 30% HDI‐PU were respectively 94% and 72%. This simple and facile strategy can be used to develop the recyclable shape memory TPU, which will have a wider range of potential applications in smart devices.