High performance composite coatings on plastics: UV-curable cycloaliphatic epoxy resins reinforced by graphene or graphene derivatives

In this work, the design and manufacture of functional composite coatings on plastic substrates were investigated. In particular, graphene nano-platelets and graphene derivatives, that is, graphene reduced oxide modified by amino organo-silane compounds, were used to reinforce a radiation curable cycloaliphatic epoxy resin. The resulting composite materials were deposited on polycarbonate. The chemical structure of the coatings was characterized by FT-IR. Physical properties of the coatings, especially thermal stability, were evaluated by differential scanning calorimetry. Chemical endurance of the coatings was tested by dipping in acidic, saline and basic environments. Special protocols were, then, developed to evaluate the friction of the coatings as well as their potential to prevent the adhesion of contaminants on their surface (i.e., anti-soiling properties). Mechanical performance of the coatings was evaluated by pencil test (pencil hardness) and progressive load scratch test (scratch hardness). Graphene-reinforced cycloaliphatic epoxy resins were found to ensure good combination of physical, chemical and mechanical properties. Therefore, they can be considered attractive functional materials to deposit on advanced plastic substrates.