Improving the comprehensive performances of epoxy coatings via poly(phthalazinone ether) modification

Epoxy resins play a vital role in anticorrosion coatings, however, the defects of poor flexibility and thermal stability of epoxy resin hinder their use in extreme environments and limit the wide range of applications for epoxy coatings. This study investigates the incorporation of high-performance thermoplastic poly(phthalazinone ether) resins (PPAEs) into bisphenol A epoxy resins (E-51) to develop a series of high performance anti-corrosion coatings. Due to the distinctive structure of the phthalazinone moiety, the flexibility and thermal stability of the epoxy coatings were greatly improved by the addition of PPAEs. The flexibility test result was reduced from over 7.5 mm to 5 mm, while the glass transition temperature ( T g ) of the coating was stabilised above 180 °C. In addition, inorganic fillers are added to plug defects such as pores inherent in epoxy coating systems. The coating provided more than 1,560 h of protection in the neutral salt spray test. At the same time, the coating maintained a high impedance modulus of 10 9 Ω⋅cm 2 (|Z| 0.01Hz ) after 4 weeks of immersion in electrochemical impedance tests. This study significantly enhances the comprehensive performance of epoxy coatings and provides a viable solution for the development of high performance epoxy anti-corrosion coatings, offering promising alternatives for corrosion protection in extreme service environments.