Shape fixing abilities of SEBS/Paraffin blends with different paraffins under conventional and reversible plasticity shape memory programming

Abstract

Poly(styrene-b-[ethylene-co-butylene]-b-styrene) (SEBS)/paraffin system is a promising class of shape memory polymers and the transition temperature of such materials could be flexibly regulated by choosing different paraffins. However, the difference in shape memory performance of SEBS/paraffin blends containing paraffin with same content but different melting temperature (Tm) has not been comparatively studied. In this work, two series of SEBS/paraffin blends containing same content paraffin (30 and 70 wt%, respectively) with Tm of 28.5 and 61.3 °C (denoted as PL and PH, respectively) were prepared and their shape fixing ratios (Rfs) under conventional shape memory (CSM) and reversible plasticity shape memory (RPSM) programming methods were investigated. It was found that these blends with the same paraffin content showed different Rfs regardless of the programming method. For example, the 30 wt% PH-containing sample exhibited higher Rf under CSM programming, while the 70 wt% PL-containing sample showed higher Rf under RPSM programming. By investigating microstructural changes, a possible explanation for the shape memory performance of SEBS/paraffin blends containing paraffin with different Tm was proposed. This work was helpful to deepen the understanding of shape memory mechanism and broaden the application of SEBS/paraffin-based shape memory polymers.