Multi-performance shape memory epoxy resins and their composites with narrow transition temperature range

Abstract Shape memory epoxy resins are one of the most widely used engineering smart polymers, which is mainly used in active deformation structures in aerospace, intelligent bionics, and other fields. A series of shape memory epoxy resins with a narrow glass transition temperature range, strong inter-segment forces and uniform cross-linked networks were designed and synthesized in this study. By adjusting the stoichiometric ratio and cross-linking density, the length of the chain segment was controlled uniformly. The glass transition temperature range reached 14–23 °C, which improved the efficiency of shape memory action. In addition, the multi-amines crosslinking agents were used to adjust the distribution of the chain segment and achieve the effect of regulating the glass transition temperature (Tg). Moreover, the addition of epoxy-terminated liquid nitrile rubber (ETBN) composites enabled toughen of systems. The elongation at break could be increased by 4 times. Furthermore, Tg, modulus and strength of composites were improved by adding high-temperature latent hardener based on the ETBN toughening system combined with two-stage curing method. The composites with narrow transition temperature range were more suitable for shape fixation and recovery temperature with higher precision and closer spacing, which meet the higher requirements in aerospace field.