Laser induced graphene-based out-of-autoclave curing of fiberglass reinforced polymer matrix composites

Fiberglass reinforced composites (FRCs) are traditionally cured in an autoclave or hot press, which are equipment known for their high energy consumption and their imposed constraints on the cured component sizes. Furthermore, current composite repair techniques usually require removing the composite part from service and using traditional composite fabrication methods to apply patches in a workshop. As an alternative to such techniques, this work presents a new out-of-autoclave (OoA) FRC curing method that relies on the Joule heating potential of transfer-printed laser induced graphene (LIG) interlayers. LIG is initially generated on polyimide substrates before then being transfer-printed onto fiberglass prepregs to form uniform surface coatings. The excellent electrical properties of the transfer-printed LIG are then exploited to in-situ cure fiberglass laminates via Joule heating effect. The LIG-coated FRCs cured through Joule heating (LIG-cured FRCs) is found to have a high degree of cure of 96%, comparable to oven-cured ones, while requiring 89.39% less specific energy. The mechanical properties of LIG-cured FRCs are measured and determined to match those fabricated using traditional approaches. Furthermore, LIG-coated fiberglass prepregs are shown capable of acting as in-situ bonding agents for the joining of two composites structures, which indicates its potential of composite repair through healing at the site of structure damage. Finally, the Joule heating effect of the LIG interlayers in cured FRCs is investigated and found to enable the fast and energy-efficient deicing of such composite structures. Therefore, the proposed OoA-curing method provides a simple and cost-efficient approach to manufacture FRCs with multifunctionality.