Solvent-Free Synthesis and Hydrophobization of Biobased Epoxy Coatings for Anti-Icing and Anticorrosion Applications

Epoxy resins are widely commercialized in the market because of their important applications such as adhesives, protective and decorative coatings. However, their usages have brought in negative impacts on the environment since approximately 70% of the epoxy resins are prepared from toxic petroleum-based precursor bisphenol. Great effort has been made on the use of biobased compounds to create an environmentally friendly epoxy resin industry. In this research, fully biobased epoxy coatings were prepared from cardanol-derived resins with furfurylamine (FA) or 1,8-diamino-p-menthane (DAPM) as the curing agent without the use of any solvent. Hydrophobization was realized by the addition of a fluorine-free additive, polydimethylsiloxane (PDMS). The thermal-mechanical and wettability properties of the coatings exhibited a strong dependency on the type of epoxy resin and curing agent. The coatings were also assessed for their anti-icing and anticorrosion performances. The fully biobased NC514-DAPM coating showed a very low ice adhesion strength at 55.0 ± 5.2 kPa. It also showed good anticorrosive properties as demonstrated in its high corrosion potential and low corrosion current. Hydrophobization by PDMS was able to further reduce the ice adhesion strength of the fully biobased coatings by 32–38%, however, its effect on the anticorrosion remains inconclusive due to the varying thicknesses of the coatings.