Mechanical properties and functionalization of Graphene oxide-Thermoplastic polyurethane polymer composites regulated by internal microstructure: From disorder arrangement to nacre-like laminated structure

Graphene oxide (GO) is a two-dimensional material known for its exceptional mechanical, chemical and electrical characteristics. Here, the mechanical properties and functionalization of GO reinforced thermoplastic polyurethane (TPU) polymer composites with GO content ranging from low to high were investigated. It shows that the GO can mix with TPU in any proportion. The microstructure changed from disorder arrangement to a regular nacre-like staggered structure, accompanied by different kinds of internal defects as the content increases, resulting in multiple peaks in the tensile properties of composite materials. The tensile strength of composites containing 80 wt% GO is 194% higher than that of pure TPU. This result is closely related to the changes in internal microstructure arrangement, the corresponding stress distribution and the transformation of damage mechanisms. Simultaneously, it shows that the composites exhibited shape memory function at low GO content of 1.5 wt% with about 100% shape recovery at 70 degrees C, and electrical conductivity and deicing function at high GO content of 80 wt% after chemical reduction, which can reach a temperature of 107 degrees C at 10 V AC. These findings will help to comprehensively understand the structural and functional integration design of GO reinforced polymer composites.Highlights Mechanical properties and functionalization of GO/TPU composites were studied. Increased GO causes the arrangement to change from disorder to a nacre-like structure. Stress distribution and damage mechanisms transformed as the GO content changed. The GO/TPU composites exhibited shape memory and deicing function. Mechanical properties and functionalization of Graphene oxide-Thermoplastic polyurethane polymer composites. image