Free-standing laser-induced graphene heaters for efficient curing and repairing of composites.

Driven by sustainable development, the energy-saving manufacturing and on-site repairing processes for fiber-reinforced polymer (FRP) composites are highly desired to replace the conventional autoclave or oven. In this work, the flexible, thin free-standing laser-induced graphene (FS-LIG) film was obtained by one-step laser irradiation on polybenzoxazine resin followed by rapid quench-peeling. The FS-LIG film showed the uniform, low-voltage driven, and long-term stable Joule heating effect. With attractive Joule performance, the FS-LIG film was developed as a heater for the out-of-autoclave fabrication of FRP composites. Compared with the conventional oven curing process, the FS-LIG-based Joule heating saved around 45% of the energy required without compromising the mechanical performance of obtained composites. Moreover, the FS-LIG film was interlayered into FRP composites to prepare the self-heating patch, which could not only provide heat for the on-site repair of structural composites but also serve as the reinforcement for mechanical properties. Furthermore, the integration of FS-LIG layer enabled the cured composites with additional functionalities including temperature and mechanical sensing to monitor the structural health of composites. This easy-fabricated FS-LIG heater showed enormous practical promise in the advanced manufacturing and repairing of composites. [ABSTRACT FROM AUTHOR]