Synthesis and properties of full bio-based thermosetting resins from rosin acid and soybean oil: the role of rosin acid derivatives

Two kinds of rosin acid derivatives were synthesized to serve as the rigid monomers to copolymerize with acrylated epoxidized soybean oil (AESO). Full bio-based thermosetting resins with satisfactory properties were then prepared. For comparison, petroleum-based divinylbenzene (DVB) was also used to copolymerize with the same AESO. The chemical structures of the synthesized rosin derivatives were confirmed by H-1 NMR, C-13 NMR and FT-IR before polymerization. The mechanical and thermal properties of the resulting thermosets were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Results demonstrated that the glass transition temperatures, tensile strength and modulus of the cured AESO were significantly improved after copolymerization with the rosin derivatives. The rosin acid derivatives showed great potential to replace petroleum-based rigid compounds for preparing soybean oil-based thermosets. The important information about how to design and synthesize more renewable thermosets with satisfactory properties was provided in this study.