MECHANICAL PROPERTIES AND CORROSION RESISTANCE PERFORMANCE OF EPOXY NANOCOMPOSITES AS ORGANIC COATING MATERIALS FOR METAL COATING APPLICATION

Abstract

Corrosion has been recognised as a cause of deterioration, failure, catastrophic accidents, and hazards in industrial and residential systems for more than 150 years, resulting in economic expenditures and societal impacts. The NACE estimates global corrosion expenses at $2,505 billion, or 3.4% of GDP. Malaysia's annual corrosion cost increased by 50.4% from $6.7 billion in 2009 to $312.4 billion in 2013. Anticorrosive properties of organic coatings, particularly epoxy coatings, have lately been studied. However, epoxy resin is brittle, has low corrosion protection, and has poor resistance to crack propagation. Hence, modifying the matrix with nanofillers is a critical approach for high-efficiency mechanical properties and corrosion protection of epoxy nanocomposites, considering well-dispersed nanofillers in the matrix. Comparison research has been conducted to examine the mechanical properties and corrosion resistance between four different nanofillers MXenes, GNPs, CNTs, and HNTs at low loading concentrations (0.1 wt.%). A solution-casting dispersion method was developed. The impact of nanofillers on mechanical properties was studied through tensile, microhardness and thermomechanical tests, while the corrosion resistance was examined by OCP and Tafel analysis. Then, the dispersion mechanism of nanofillers was evaluated by SEM and UV-Vis Spectrophotometer analysis. The improved tensile properties and microhardness were observed in all types of nanofiller/epoxy; HNTs and MXenes led to the highest improvement in tensile properties and microhardness, respectively, compared to neat epoxy. CNTs and GNPs exhibited remarkable improvement in storage modulus and Tg value, respectively. The OCP and Tafel analysis results revealed that the coatings reinforced by MXenes provided the most excellent protective performance with an inhibitory efficiency value of up to 99.999%. Besides, this work opens that HNTs exhibited better mechanical performance but poorer corrosion resistance ability due to their hydrophilic nature. The SEM analysis indicated that the morphological surfaces aligned with the tensile test result. The UV Vis spectrophotometer analysis revealed that solvent addition affects the dispersion interaction, further influencing the composite properties. The findings concluded that the inclusion of nanofillers with large aspect ratios improved mechanical and barrier properties. In contrast, agglomeration had the opposite effect, suggesting that if nanofiller homogeneity could be improved, further improvement properties may be expected. Overall, this study came to the conclusion that the improvement of nanocomposite properties is influenced by the geometry and dispersion rate of nanofillers.