rGO as an adhesion enhancer of fusion bonded epoxy coatings
Fusion-bonded epoxy (FBE), an epoxy-based powder coating, has been widely used in some sectors due to its quick and easy application and the reduction of waste material. FBE is a high-performance composite with approximately 30 wt% microparticles, and the challenge that has now been addressed is to improve the coating properties by adding a low content of graphene.
In a recently conducted work, new coatings based on FBE and thermally reduced graphene oxide (rGO) were developed and prepared by two different processes: in one case, highly thermally stable and low functionalised graphene (rGO-tre with 4.6 % oxygenated groups) and in the other case, highly exfoliated and more functionalised graphene (rGO-tr with 9.8 % oxygenated groups). FBE/rGO-tr and FBE/rGO-tre nanocomposites were produced in concentrations of 0.1, 0.3, 0.5 and 1.0 wt% in a planetary ball mill.
Coated steel plates were heated in a conventional oven at 204 °C, and the curing of the material was confirmed by using differential scanning calorimetry (DSC) analysis. The addition of rGO-tr (1.0 wt%) and rGO-tre (0.5 wt%) improved the adhesion of the nanocomposite coating in the wet test by 104 % and 95 %, respectively, when compared with neat FBE coatings. Small gains in abrasion and hardness were also observed. In addition to the tendency to reduce indentation (micro and nano), it was possible to observe a better recovery of the FBE with the addition of rGO-tr and rGO-tre after the deformation carried out by the tip.
The study has been published in Progress in Organic Coatings, Volume 171, October 2022.