Abstract

Novel nanocomposites were synthesized and studied, comprising of graphene nanoplatelets (GNPs) or reduced graphene oxide (rGO) or 3-glycidoxypropyltrimethoxysilane (GLYMO-rGO) as nanofillers, dispersed in epoxy resin matrices. Due to limited petrochemical resources and environmental concerns, biopolymers are becoming increasingly attractive, allowing a more sustainable production and growth. Therefore, both fossil-based and bio-based epoxy resins were studied. New graphene/epoxy nanocomposites were developed, following a facile solvent-free approach, adding the above graphene related materials (GRMs) in the amine hardener, simplifying the experimental procedure, and lowering manufacturing cost. The addition of GRMs caused an increase in the degree of curing of the epoxy systems, a reduction in activation energy, improved thermal stability, mechanical properties, and lap shear strength. More specifically, in the fossil-based resin, an increase in thermal stability by the addition of GNPs was identified in the range of 360–580℃ using TGA. In terms of mechanical properties, addition of an optimum amount of 0.5%wt of GNPs improved the Young’s Modulus by 37%. Nanoindentation measurements showed a 9.4% improvement in hardness at 0.7%wt GNPs. In the bio-based resin, addition of 1.5wt% of GLYMO-rGO into the epoxy matrix was found to increase the degree of cure by up to 12% and glass transition temperature by 14℃. Mechanical testing showed that the addition of 0.05wt% GLYMO-rGO improves young’s modulus and tensile strength by 60% and 16%, respectively, compared to neat epoxy. The resins enhanced with GRMs were also used as an adhesive to bond CFRP/CFRP and CFRP/aluminium adherents. The addition of 0.1wt% GLYMO-rGO into the adhesive and CRFP adherents showed improved lap shear strength by 23.6% compared to neat resin, while in the case of CFRP/Aluminium joints the increase was 21.2%. These novel nanocomposite materials can be used to design lightweight materials for energy-efficient and safe vehicles.