Effect of graphene nanoparticles on suspension viscosity and mechanical properties of epoxy-based nanocomposites

Abstract

The use of nanocomposite materials in many industrial applications has been increasing in recent years due their superior mechanical performance and reduced weight. Among the nanoparticles available for use in nanocomposites, graphene appears as one of the most promising due to its excellent mechanical and electrical properties. Therefore, the objective of this work is to analyse the properties of an epoxy resin and how they were affected by the presence of graphene. Epoxy resin viscosity, contact angle between graphene particles and resin, effect of mixture condition on polymerization rate and shrinkage tests were performed. The effects of the pre-cure temperature, between 7ºC and 40ºC, and hardener mixing times on the mechanical properties of the nanocomposite were studied. It was observed that the presence of graphene (0.5 wt.%) in the epoxy resin increased the viscosity by 4.2% and the shrinkage increased from 3.2 % to 5.7%. It was also possible to conclude that higher hardener mixing times and lower pre-cure temperatures had a very positive impact on the mechanical properties. Concerning the graphene content, the best mechanical properties were obtained with 0.5 wt.%, for which an increase of maximum bending stress between 8% and 31% was observed, depending on the pre-cure temperature.