不同苯并三氮唑(BTA)添加量对BTA@PHVA/PEI环氧涂层防护性能的影响OA北大核心CSTPCD

Heterogeneous gels (BTA@PHVA/PEI) loaded with benzotriazole (BTA) were successfully prepared by free radical polymerization and added to epoxy coatings to prepare BTA@PHVA/PEI epoxy composite coatings. The effect of different benzotriazole additions on the protective properties of BTA@PHVA/PEI epoxy composite coatings was investigated by preparing BTA@PHVA/PEI with different BTA additions. FT-IR, SEM and TG were used to investigate the structural properties of the prepared BTA@PHVA/PEI. The findings revealed that the surface of the PHVA/PEI hybrid gel created a large number of folds and pores due to electrostatic repulsion, which provided space for storing water and loading BTA. The loading of BTA had little effect on the chemical structure of the PHVA/PEI hybrid gel. The loading of BTA in the BTA@PHVA/PEI prepared with different BTA additions was 10.7wt.％, 14.2wt.％ and 18.1wt.％, respectively. The prepared coatings (EP coating, BP-1/EP coating, BP-2/EP coating and BP-3/EP coating) were immersed in a 3.5wt.％ NaCl solution to simulate seawater immersion tests. Adhesion tests, electrochemical impedance spectroscopy and electron microscopy were used to evaluate and analyze the corrosion resistance of coatings. The results showed that the BTA@PHVA/PEI epoxy coatings had higher adhesion compared with the epoxy coatings due to the siloxane structure in BTA@PHVA/PEI which improved the compatibility of the gel with the organic coating and increased the degree of cure of the epoxy coating. After 14 days of immersion, the adhesion of BP-1/EP coatings, BP-2/EP coatings and BP-3/EP coatings decreased by 55.7％, 53.9％ and 58.2％, respectively, which was less than the reduction in adhesion for EP coatings (60.4％). The reason for that while the siloxane structure increased the degree of curing of the epoxy coatings, the N and Zn atoms in the BTA@PHVA/PEI in the BP/EP coatings enhanced the adhesion. At the same immersion time, the BTA@PHVA/PEI coatings always had higher impedance values, while the impedance values of the EP coatings decreased to 5.39×104 Ω·cm2. The impedance of BP-2/EP remained at 3.36×105 Ω·cm2 after 300 h of immersion, which was due to the fact that the BTA in BP-2/EP was released to form a corrosion inhibitor film on the surface of the metal substrate and retarded the corrosion of the metal at the coatings defects. The corrosion resistance of the coatings with the addition of BTA was significantly better than that of the EP coatings, which was due to the fact that the corrosion performance of the coating was enhanced by the release of the adsorbed film formed by BTA on the substrate surface by BTA@PHVA/PEI. In summary, heterogeneous condensed BTA@PHVA/PEI loaded with the corrosion inhibitor BTA is successfully prepared; the siloxane structure in PHVA/PEI increases the crosslink density of the epoxy coatings and reduces the permeability of water and corrosion ions, resulting in higher adhesion of the BP/EP coating. Under the same experimental conditions, the protection effect of BTA@PHVA/PEI epoxy coating is superior, which is mainly related to the formation of an adsorption film on the surface of the metal substrate by the lone electron pair of N atoms in BTA with the empty orbitals of Fe atoms, and the formation of a dense barrier on the metal surface by the three-dimensional network structure of PHVA/PEI gel.