Al2O3/graphene reinforced bio-inspired interlocking polyurethane composites with superior mechanical and thermal properties for solid propulsion fuel

Nature always provides intelligent strategy for developing advanced materials with superior properties. In this study, by cloning the reinforcing mechanisms in nacre , a nacre-inspired Al 2 O 3 /graphene/polyurethane (PU) composite with hybrid hierarchical structure, was successfully fabricated. The structural interlocking interface, together with its excellent force bearing property, leads to exceptional mechanical performance. Compared with pure PU, the bio-inspired, Al 2 O 3 /graphene reinforced PU composite demonstrates a unique improvement in Young's modulus (211%), tensile strength (41%), and compressive modulus (145%). Moreover, the thermal conductivity of Al 2 O 3 /graphene/PU composite reaches to 0.502 W m −1  K −1 , enhanced by 141% compared with pure matrix, showing very high enhancement efficiency, which is attributed to the multilevel aligned structure and multi-contact conductive pathway inside the composite. This design strategy offers a promising approach to handling high mechanical and thermal performance of solid propulsion fuel by synthesizing bio-inspired architecture.