Soybean oil-based thermoset reinforced with rosin-based monomer

A full bio-based cured resin was synthesized by copolymerization of acrylated-epoxidized soybean oil (AESO) and 2-acrylamidoethyl dehydroabietic acid (DHA-HEMAA). The rigid rosin-based monomer 2-acrylamidoethyl dehydroabietic acid was first prepared from dehydroabietic acid and N-hydroxyethylacrylamide, which was characterized by nuclear magnetic resonance and Fourier transform infrared (FTIR) spectrometry techniques. The cured resin was then synthesized and characterized by FTIR spectroscopy, differential scanning calorimetry, dynamic thermomechanical analysis, and thermogravimetric analysis, as well as using a Kruss tensiometer and a universal testing machine. The results indicated that the resin cured with rosin-based monomer exhibited excellent thermomechanical properties. The crosslink density and thermal stability of cured samples containing DHA-HEMAA at molar ratio between 10 and 30% were higher than those of AESO/DHA-HEMAA0 sample. With increasing DHA-HEMAA content, the glass transition temperature (Tg), elongation-at-break, and tensile strength of samples increased, in the stated order, from 16 to 38 °C, from 24 to 45.8%, and from 1.7 to 6.5 MPa. Due to DHA-HEMAA with a hydrophenanthrene structure, the θ values increased with the increase of DHA-HEMAA molar ratios. The full bio-based rosin thermosetting resins may have great potentials in practical application fields, such as coating, adhesive, and packaging materials.