No abstract

No abstract

The green corrosion inhibitor is used in epoxy coating system by extraction of turmeric in dimethyl formamide (DMF). The major component extracted is curcumin. Three concentrations have been studied for anticorrosive performance i.e., X, 2X and 4X. Among this X based concentration showed the best performance. Magnesium hydroxide Mg(OH) 2 has been treated with 3-glycidoxypropyltrimethoxysilane (GPTMS). It was added into coating formulation at three concentrations namely 5%, 7% and 10% (w/w). The best anticorrosive performance has been observed for 5% concentration. As the concentration increases the anticorrosive performance decreases but flame retardancy increases. The 7% Mg(OH) 2 concentration has been combine studied with turmeric X concentration. It is observed that combination of extract with Mg(OH) 2 gives good anticorrosive performance as well as flame retardant properties. The anticorrosive performance is evaluated by salt spray and electrochemical impedance spectroscopy (EIS) and flame retardancy is evaluated by Limiting oxygen index (LOI) and UL-94 study.

Epoxy coating system with enhanced corrosion resistance was prepared. The epoxy resin was used as a base resin and polyamine was used as its hardener. The ashes of Karwand (Carissa carandas) seeds and Pumpkin (Cucurbita pepo) seeds were used to increase the anticorrosive performance of the coating. These ashes were prepared by the method of calcination in a muffle furnace by heating at 800°C for 2 hours. Surface treatment was done to introduce amine functionality to the ash which was confirmed by FTIR analysis. The surface treated ash was then added into the epoxy-amine system at 1%, 3%, 5% (w/w) of the total epoxy-amine coating system. The coating was then applied to mild steel panels by the method of brush coating and was tested for mechanical properties and chemical resistance. The coating was also subjected to the salt spray test for analysis of anticorrosive performance. It was observed that the anticorrosive performance of the coating increases as the concentration of ash in the epoxy-amine system increases. This is due to ash constituents such as ZnO, MgO, Fe2O3, CuO etc. which work either by barrier mechanism or passivation mechanism and prevent corrosion. The scratch resistance and the hardness also increased with an increase in the concentration of ash. This is because the ash in the epoxy-amine system acts as filler in the coating. Also, surface treatment introduces amine functionality which reacts with the epoxy group and tends to increase hardness. Thus, presence of inorganic elements in the ash and surface treatment are prime factors responsible for enhancing corrosion resistance of the system.

The ash of groundnut shell, cashew nut shell, tamarind shell, rice husk and sugarcane bagasse has been used as a modifier for epoxy-amine coating. The ash has been made by the calcination process. Then it was surface treated to introduce amine functionality on the periphery. The ash has been added at 1%, 3% and 5% (w/w) of the total binder system. The ash has been characterised by Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction analysis (XRD) for the confirmation of its surface treatment. The coating has been characterised for mechanical performance, chemical resistance and anticorrosive properties. It is seen that with the addition of ash, hardness properties of the coating enhances. In anticorrosive performance it is observed that with the addition of ash, the anticorrosive performance of the virgin coating increased. The ash enriched with inorganic elements silicone dioxide (SiO 2), magnesium oxide (MgO), zinc oxide (ZnO), aluminium oxide (Al 2 O 3), ferric oxide (Fe 2 O 3). These are the key components to enhance the hardness properties and anticorrosive performance of the coating.