Environmentally sustainable epoxy nanocomposite coating reinforced with chitosan derived nitrogen doped graphene for enhanced corrosion resistance and mechanical performance

The current study evaluates the anticorrosive performance of Epoxy coating augmented with a distinctive, environmentally safe, nitrogen-doped graphene. A simple, green, and single-step cost-effective route for synthesis graphene nanosheets doped with nitrogen (Gr) has been developed using direct-solvothermal treatment of chitosan, under gentle conditions. XRD, FTIR, SEM, XPS and Raman spectroscopy were employed to characterize the microstructure characteristics of N-doped graphene. Well separated flatten morphology with folding characteristics and extremely extended considerable average lateral dimensions further than 1.27 mm was detected. Graphene was successfully integrated into epoxy coatings on carbon steel substrates with different tiny graphene concentrations < 0.04 wt%. The coatings' corrosion resistance capabilities and accelerated durability tests were studied, including salt spray corrosion, bending, impact, adhesion, abrasion properties, wear resistance, and hardness. Comprehensive mechanical performance was investigated. Understanding the microstructural characteristics of Gr, the interface character of Gr/Epoxy coating composites with different Nanofiller loading and how these affect both the mechanism of the enhancement of corrosion protection process and their tensile behavior, were a focal point of interest. Remarkably, the coating with just 0.02 wt% Gr exhibited a 70% reduction in wear index compared to neat epoxy, along with significant enhancements in mechanical toughness showing a 573% increase in ultimate toughness and a 993% increase in toughness at fracture. These exceptional improvements are attributed to the strong interfacial bonding between Gr and the epoxy matrix, as well as the tortuous path created by the well-dispersed graphene sheets, which effectively dissipates energy during crack propagation. The findings reveal a pronounce toughening and strengthening effects for epoxy composites from nitrogen doped graphene reinforcement paving the way for "green" and mechanically superior structural composites.