A brief discussion on how to improve the structure and corrosion resistance of coating films

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A brief discussion on how to improve the structure and corrosion resistance of coating films. The basic properties of coatings are determined by the film-forming resin, which is primarily an organic polymer compound; the inherent characteristics of such organic polymers are determined by the structure of their molecular chains. Therefore, the main factors affecting the performance of anti-corrosion coatings can be attributed to the structure of the film-forming resin. For example, phenolic resins, polyethylene resins, etc., possess good chemical resistance, water resistance, and corrosion resistance. Resins with ester-linked segments, such as alkyd resins and polyester resins, are susceptible to hydrolysis by alkalis; therefore, they have poor resistance to chemical corrosion ； Epoxy resins and phenolic resins containing ether bonds possess excellent corrosion resistance. It is worth noting, however, that each resin contains various chemical structures and groups, and these structures and groups interact with one another. Additionally, the corrosive agents encountered and the corrosion environment vary as well. Therefore, when analyzing the impact of the structure of the film-forming resin on anti-corrosion coatings, a detailed analysis is necessary in order to achieve the desired results. In general, structurally, coatings formed from carbon-chain polymers exhibit better corrosion resistance than those made from hetero-chain polymers. When hydrogen atoms in the carbon chain are replaced by elements such as fluorine and chlorine, the smaller size of these elements allows them to fill in the gaps between carbon-carbon bonds and provide shielding effects. Additionally, the bond energies of fluorine-carbon and chlorine-carbon bonds are higher than that of carbon-carbon bonds, which further enhances their corrosion resistance. Furthermore, the cured coating should contain as few low-molecular-weight compounds as possible, and the presence of active groups such as hydroxyl, carboxyl, aldehyde, and amino groups should be avoided. The number of double bonds in the cured coating film should also be reduced to a minimum, in order to avoid the creation of too many sites that can act as catalysts for corrosion, thereby accelerating its progression. Once the film-forming resin is determined, an increase in its polymerization degree leads to improved strength, wear resistance, softening point, chemical stability, and weather resistance of the paint film.