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

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. Shape memory epoxy resins are one of the most widely used engineering intelligent polymers, mainly used in aerospace, intelligent bionics, and other fields of active deformation structures. A series of shape memory epoxy resins with a narrow transition temperature range, showing strong inter-segment forces and regular uniform cross-linked networks are designed and synthesized. By adjusting the stoichiometry and cross-linking density, the length of the segments is uniformly controlled. The glass transition temperature range can reach 14–23 °C, which improves the efficiency of shape memory action. Moreover, the addition of epoxy-terminated liquid nitrile rubber (ETBN) composites can toughen the system. Furthermore, combing the two-stage curing method, and selecting the nano-particle high-temperature latent curing agent, the super curing effect is achieved, Tg, modulus and strength of composites are improved. The resulting composites are appropriate for shape fixation and recovery temperature with more precision and closer distance between, which can meet the higher requirements of the aerospace field. . • A series of shape memory epoxy resins and their composites with narrow glass transition range (14–23 °C). • Strong segment force and uniform crosslinking network improve the temperature sensitivity and control accuracy. • Multi-amine crosslinkers containing different active hydrogens cause different segment distributions of SMEP with tunable Tg. • The added ETBN formed a sea-island structure, which increased the elongation at break by 4 times. • Based on ETBN toughening and combining two-stage curing technology, the Tg, modulus and strength of the system were improved.