Bio-based one-component epoxy resin
In a recently conducted work, an epoxy resin produced from an agroindustrial byproduct, cashew nutshell liquid (CNSL), was used for manufacturing a one-component anticorrosive epoxy coating. CNSL-based epoxy resin (e-CNSL) was synthesised using a solvent-free methodology with performic acid generated in situ.
The chemical structure of resin was evaluated and the curing parameters of the epoxy-phenol system with 1-methylimidazole (1-MIM) as an accelerator were investigated. The use of only 5% by weight of 1-MIM was efficient to catalyse the reaction, obtaining the lowest cure temperature (150 °C). The coating showed high crosslinking and good thermal-mechanical performance, where the initial decomposition temperature was 200 °C and glass transition temperature was 30 °C.
The anti-corrosive performance of e-CNSL/MIM5 exposed to salt spray and 3.5% w/v NaCl solution was studied. The coating presented high impedance module and high adhesive property, suffering low delamination during the tests. According to the study, the one-component bio-based coating developed is promising to be applied for corrosion protection purposes.
The study has been published in Progress in Organic Coatings, Volume 167, June 2022.