Simultaneous reduction and surface functionalization of graphene oxide for enhancing flame retardancy and thermal conductivity of mesogenic epoxy composites

Graphene oxide (GO) is reduced and surface functionalized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide simultaneously. This functional reduced graphene oxide (F-rGO) with better thermal stability can be used as a nano-filler to improve the flame retardancy, mechanical properties and thermal conductivity of mesogenic epoxy (EO). Due to the presence of an oriented structure, EO is an intrinsic highly thermal conductive polymer compared with common polymer. After being filled with F-rGO, the ordered domains in the EO matrix are connected by F-rGO. As a result, the thermal conductivity coefficient of F-rGO/EO composite is increased by 30.8% compared with pure EO. The dynamic mechanical analysis results indicate that E' of F-rGO/EO is 26.7% higher than that of EO. Because of the stable structure of F-rGO, F-rGO/EO is self-extinguishing. The total heat release of F-rGO/EO-15 is 24.1 kJ g(-1), which is 5.6 kJ g(-1) lower than that of EO. (c) 2016 Society of Chemical Industry