Abstract
Waterborne coatings are of growing importance in appliance, automotive refinish, concrete, traffic marking and high performance coatings due to increasing environmental regulation to reduce volatile organic compounds (VOC) and ease of handling. The resins commonly used for conventional solvent borne coating are usually modified by increasing their hydrophilic nature prior to being incorporation into a waterborne coating formulation. Sol gel process is one of the relatively new approaches to develop environmentally compliant waterborne coating system. Sol gel processing involves hydrolysis and condensation of organically modified silanes with traditional alkoxide precursor, which results in organic inorganic hybrid sol for coating.
In this paper, methyltrimethoxysilane (MTMOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) were used as precursors to prepare waterborne organic inorganic hybrid coating on the aluminum alloy surface. Two amino-silane namely N-(2 -aminoethyl)-3- aminopropyltrimethoxysilane (AEAP-TMOS) and 3 - aminopropyltriethoxysilane (AP-TEOS) and and Hexakis (methoxymethyl) melamine (HMMM) were used as crosslinking agents. The anticorrosive behavior of developed coatings was investigated by analyzing potentiodynamic polarization curves and salt spray. Structural characterization of the hybrid coatings was performed using scanning electron microscopy (SEM) and FT-IR reflectance spectroscopy (FTIR). The performance of the coating was also evaluated for various end use properties like scratch resistance, hardness, adhesion, flexibility.
The measurements show that the improvement of the corrosion resistance of coated aluminum sample by forming a physical barriers, which effectively separates substrate from its environment. The end use properties of coating were found to be excellent. Also, the effect of corrosion inhibitor on performance of coating was also evaluated.
