IMIDAZOLE CORE AMINE/EPOXY AND RHA SILICA BASED COMPOSITES COATINGS FOR CORROSION RESISTANT APPLICATION

Abstract

Imidazole core monoamine (IMA) was synthesised and used as a hardener for epoxy resin. The epoxy resin was reinforced with varying weight percentages of 3-glycidoxypropyltrimethoxysilane (GPTMS) functionalized rice husk ash bio-silica to obtain respective composites. Their composite morphology was studied using SEM analysis. The cure behaviour of imidazole core diamine hardener and DGEBA epoxy resin was studied. The thermal stability of the corresponding epoxy matrix and bio-silica reinforced epoxy composites were studied by thermogravimetric analysis (TGA). The values of limiting oxygen index calculated from TGA data infer that all the samples of epoxy matrix and composites possess good flame retardant behaviour. In order to ascertain their hydrophobic behaviour, the water-contact angle measurement studies were carried out. The values of contact angle obtained for neat IMA/DGEBA matrix is 84°, where as that of 1, 3, 5, 7 and 10wt% bio-silica reinforced IMA/DGEBA are 87°, 90°, 93°, 95° and 98° respectively. IMA/DGEBA matrix and functionalised bio-silica reinforced IMA/DGEBA composites were coated on the mild steel specimens and their corrosion resisting behaviour was studied by electrochemical impedance spectroscopy and potentiodynamic polarisation. Data resulted from corrosion studies (Nyquist plot and Tafel plot) inferred that among the coated specimens studied, the specimen coated with 7 wt% bio-silica reinforced IMA/DGEBA matrix exhibits the highest corrosion resisting efficiency due to its water repellent character and morphology.