Preparation of new surface coating based on modified oil-based polymers blended with ZnO and CuZnO NPs for steel protection

Abstract

In our paper, we have synthesized modified PEA and alkyd resin by replacing the new source of polyol (SDEA) which was confirmed by different analyses such as IR, and 1HNMR spectra. A series of conformal, novel, low-cost, and eco-friendly hyperbranched modified alkyd and PEA resins were fabricated with bio ZnO, CuO/ZnO) NPs through an ex-situ method for mechanical and anticorrosive coatings. The synthesized biometal oxides NPs and its composite modified alkyd and PEA were confirmed by FTIR, SEM with EDEX, TEM, and TGA, and can be stably dispersed into modified alkyd and PEA resins at a low weight fraction of 1%. The nanocomposite coating was also subjected to various tests to determine their surface adhesion, which ranged from (4B-5B), physico-mechanical characteristics such as scratch hardness, which improved from < 1.5 to > 2 kg, gloss (100–135) Specific gravity (0.92–0.96) and also chemical resistance test which passed for water, acid, and solvent except alkali, was poor because of the hydrolyzable ester group in the alkyd and PEA resins. The anti-corrosive features of the nanocomposites were investigated through salt spray tests in 5 wt % NaCl. The results indicate that well-dispersed bio ZnO and CuO/ZnO) NPs (1.0%) in the interior of the hyperbranched alkyd and PEA matrix improve the durability and anticorrosive attributes of the composites, such as degree of rusting, which ranged from 5 to 9, blistering size ranged from 6 to 9, and finally, scribe failure, which ranged from 6 to 9 mm. Thus, they exhibit potential applications in eco- friendly surface coatings. The anticorrosion mechanisms of the nanocomposite alkyd and PEA coating were attributed to the synergistic effect of bio ZnO and (CuO/ZnO) NPs and the prepared modified resins are highly rich in nitrogen elements, which might be regarded as a physical barrier layer for steel substrates.