Preparation and Properties of Corrosion-Resistant Coatings From Waterborne Polyurethane Modified Epoxy Emulsion

Abstract

Corrosion of metal products can seriously affect their reliability. The application of coatings is the most widely used method of corrosion protection due to the desire for easy application and low cost. Most of the present corrosion-resistant coatings are solvent coatings. Due to the high content of volatile organic compounds, the use of solvent coatings is restricted. Currently, the corrosion resistance of waterborne coatings is much lower than that of solvent coatings, so research and development of waterborne corrosion-resistant coatings are necessary and valuable. A corrosion-resistant waterborne polyurethane modified epoxy (WPUME) emulsion was prepared and characterized by Fourier transform infrared (FTIR) spectra, transmission electron microscopy, and thermal gravimetric analysis. The particle size, dispersion, and solid content of the emulsion were tested by laser-scattering equipment and a weighing method. Coatings were prepared based on the emulsion, and the properties (i.e., water absorption rate, salt spray resistance, and flexibility) of the coatings were tested by the standard method, respectively. Results show that the synthesis reaction accords well with the molecule design, and the average diameter of the particles in the emulsion is 100 nm approximately. The cured coating, which is coated on tinplate sheets, has good flexibility and can withstand the salt spray test for more than 60 days (i.e., 1,440 h). The emulsion has many potential practical applications in the protection of metal materials.

Study on the Synthesis and Properties of Waterborne Polyurea Modified by Epoxy Resin

“…In Figure 2 , compared with curve a, the absorption peak at 829 cm −1 in curve b was attributed to the bending vibration generated by the replacement of two pairs of hydrogen atoms of the benzene ring in the epoxy resin [ 21 ]. Due to the ring-opening reaction of the epoxy group, no absorption peak of the epoxy group was observed at 910 cm −1 [ 22 , 23 ].…”

Mg alloy surface immobilised with caerin peptides acquires enhanced antibacterial ability and putatively improved corrosion resistance

“…Firstly, their capacity to increase the corrosion resistance of Mg alloy was assessed. Previous studies showed that certain types of PU coating can provide protection on Mg alloys from corrosion [78], yet did not present any effect of bacterial resistance. The acidic metabolites secreted/excreted by bacteria (depending on the strains) can cause further corrosion once these bacteria adhere to the surface [79].…”

Bio-Based Waterborne Polyurethane Coatings with High Transparency, Antismudge and Anticorrosive Properties

“…However, the antismudge property of coatings was unsatisfactory due to the low cross-linking degree and massive hydrophilic polar groups. To improve the antismudge property of coatings, a second component with a few functional reactive groups, such as hexamethoxymethylmelamine (HMMM) and hexamethylene diisocyanate trimer (HDIT), should be added additionally in the dispersion, prior to the coating forming stage, to ensure the hydrophilic polar groups are consumed during the coating curing process. , Although this method could obtain NP-GLIDE WPU coatings with antismudge property at a low PDMS content (1.0–5.0 wt %), the coating preparation process is complicated by adding the second reactive component to compensate for the lack of cross-linking degree to improve the water-resistance properties.…”