Synthesis of Cyano-Containing Epoxy Precursor from Vanillin for Engineering Multifaceted Performance-Enhancing Resins

Interest in producing chemicals and thermosets from sustainable resources is growing, yet their moderate performance drastically undermines their potential applicability. Herein, an aryl dinitrile epoxy precursor (DVN-EP) was developed from vanillin. After curing with 4,4′-diaminodiphenyl sulfone (DDS), cyano-containing resin (DVN-EP/DDS) was produced with eminent comprehensive properties on account of the dual-cross-linked network formed by the epoxy-amine reaction and the further cyclotrimerization of cyano groups. In particular, the glass transition temperature, storage modulus, char yield (at 800 °C in N2), and Young’s modulus of the DVN-EP/DDS were 201 °C, 2795 MPa, 47.4%, and 5034 MPa, respectively, all much higher than those of the cyano-free counterpart (DMG-EP/DDS). Moreover, the cyano dipole–dipole pairings combined with the H-bonding interactions contributed to a tremendously increased lap shear strength of up to 7.18 MPa as well as good energy dissipation and damping capacity. The rationally designed dual-cross-linked network strengthening mechanism reported here offers an important and universal strategy for significantly enhancing the comprehensive properties of thermosets.