Cardanol modified fatty acids from camelina oils for flexible bio-based acrylates coatings

Abstract

Novel bio-based acrylate was designed through the epoxy ring-opening reaction of cardanol glycidyl ether (CGE) with fatty acids from camelina oil (FACO), followed by epoxidation of unsaturated chains and then acrylation of the epoxides. Cardanol- and camelina oil-based acrylates were also respectively synthesized for comparison purposes. The bio-based acrylate coatings were then produced under UV-radiation from the acrylates monomers with an addition of a photoinitiator. Polymerization of the acrylates and synthesis of the monomers were observed using Fourier transform infrared (FTIR) spectroscopy, and the chemical structures and acryl contents of the acrylates were confirmed by proton nuclear magnetic resonance (1H NMR). The mechanical and thermal properties of the cured acrylates were evaluated using tensile test, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). Observation of resistances to water, solvent, and hydrolytic degradation were conducted to water and toluene uptake test, methyl ethyl ketone (MEK) rub test, and a degradation test under sodium hydroxide solution. Gel content was measured to evaluate performance of the coatings, and other coating performances including gloss, adhesion, and pencil hardness were determined using the wood panel coated with the cured acrylates. Compared to acrylated epoxidized soybean oil (AESO) coating, the acrylate derived from the cardanol modified fatty acids showed higher tensile strength, hardness, glass transition temperature, thermal decomposition temperature at maximum degradation rate, and resistances to solvent and hydrolytic condition of the cured coating. Therefore, the newly designed acrylate is a great alternative to AESO.