Green preparation of robust hydrophobic bio-based epoxy resin with low dielectric constant

Epoxidized soybean oil (ESO) thermosets show poor performance owing to the low cross-linking density and flexibility of their backbone structure. Herein, fully bio-derived benzoxazine (GD) cured ESO thermosets (PGEs) with high-performance were prepared through a green process. As a curing agent, GD improved the cross-linking density and rigidity of ESO resins. Moreover, different types of hydrogen bonds formed in the PGEs, further strengthening the intermolecular interactions. Therefore, the glass transition temperature ( T g ) and tensile strength of PGEs attained 93 °C and 34 MPa, respectively, which are higher than those reported for conventional ESO resins. Additionally, PGEs exhibited substantial hydrophobicity and a low dielectric constant, which can be associated with complex intermolecular and intramolecular hydrogen bonds within the thermoset network. Furthermore, as the GD content in PGE increased, the dielectric constant and water absorption of the polymer reduced to 2.72 % and 0.52 %, respectively. Herein, the preparation of novel all-biological ESO thermosets using GD as the curing agent is reported, providing a green and convenient strategy for the design of high-performance ecological materials.