Itaconic Acid as a Green Alternative to Acrylic Acid for Producing a Soybean Oil-Based Thermoset: Synthesis and Properties

In this paper, itaconic acid was monomethylated with methanol to produce monomethyl itaconate, and then monomethyl itaconated epoxidized soybean oil (IESO) was obtained by melt ring-opening esterification of monomethyl itaconate with ESO. For comparison, acrylated epoxidized soybean oil (AESO) was also synthesized from ESO and acrylic acid with the same synthetic method. The chemical structures of monomethyl itaconate, IESO, and AESO were characterized in detail by differential scanning calorimetry (DSC), FTIR, and 1H NMR. The isothermal thermogravimetric analysis at 30, 60, and 90 °C indicated that monomethyl itaconate exhibited extremely low volatility even at 90 °C, while acrylic acid volatilized very fast even at 30 °C, which suggested that monomethyl itaconate could be used as a green alternative to acrylic acid. Under UV radiation, IESO showed good copolymerization ability with reactive monomers such as glycidyl methacrylate modified itaconic acid (IG), trimethylolpropane triacrylate (TMPTMA), and styrene. The cured neat IESO exhibited similar properties to the neat AESO, and the IESO/reactive monomers systems showed higher glass transition temperature (Tg), modulus, and comparable or better tensile strength and coating properties than the AESO/reactive monomers systems.