Effect of Silica/Graphene Nanohybrid Particles on the Mechanical Properties of Epoxy Coatings

Abstract

Epoxy resins are used as coating materials, but the practical use of epoxy coatings in industries is limited due to their weak mechanical properties. In the present paper, different amounts of silica nanoparticles ( $$\hbox {SiO}_{2})$$ and graphene nanoplatelets (GNPs) were introduced separately and together into an epoxy coating matrix as reinforcements. Graphene, a newly discovered carbon allotrope, has been found to improve the mechanical properties of the polymer composites in which it is dispersed. Silica particles are also known to improve the mechanical properties of composites. In this study, mechanical, physical and thermal properties of the epoxy coatings are considered as multidimensional by the macro- and microanalyses. The experimental results showed that after the addition of GNPs into the epoxy matrix, the flexibility and impact resistance of the coatings increased by 8.3 and 157.1%, respectively, in relation to neat epoxy. The microhardness increased by 53.8% and penetration depth, which is indicative of the scratch resistance, decreased by 29.7%, with the addition of $$\hbox {SiO}_{2}$$ –GNPs nanohybrid. A remarkable synergistic effect was observed between the GNPs and $$\hbox {SiO}_{2}$$ , which improved the hardness and the scratch resistance of the epoxy coatings.