Thermally sprayable grafted LDPE/nanoclay composite coating for corrosion protection

Application of thermally sprayable polymeric coating is one of the methods for protection of mild steel against corrosion. In the present study, grafting of low density polyethylene (LDPE) was carried out with maleic acid at different concentrations (3, 5, 8 and 10%, w/v) using γ-irradiation technique. LDPE, γ-irradiated LDPE and grafted LDPE (LDPE-g-MAc) were characterized by chemical method, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA) and melt flow index (MFI). Grafted LDPE was pigmented with nanoclay (NC) at varying concentrations (1, 2, 3 and 4 wt.%) using melt mixing method. Pigmented compositions were evaluated for their mechanical properties and dispersion characteristics using X-ray diffraction (XRD). LDPE-g-MAc/nanocomposite with 3 wt.% nanoclay showed superior mechanical properties and maximum d-spacing value. This composition was applied on grit blasted mild steel specimens by flame spray technique and evaluated for adhesion strength, abrasion resistance and resistance to corrosion in different exposure conditions. Electrochemical Impedance Spectroscopy (EIS) technique was also employed to study the corrosion resistance behavior of the nanocomposite coating.