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

Interest in producing chemicals and thermosets from sustainableresources is growing, yet their moderate performance drastically underminestheir potential applicability. Herein, an aryl dinitrile epoxy precursor(DVN-EP) was developed from vanillin. After curing with 4,4 '-diaminodiphenylsulfone (DDS), cyano-containing resin (DVN-EP/DDS) was produced witheminent comprehensive properties on account of the dual-cross-linkednetwork formed by the epoxy-amine reaction and the further cyclotrimerizationof cyano groups. In particular, the glass transition temperature,storage modulus, char yield (at 800 degrees C in N-2), andYoung's modulus of the DVN-EP/DDS were 201 degrees C, 2795 MPa,47.4%, and 5034 MPa, respectively, all much higher than those of thecyano-free counterpart (DMG-EP/DDS). Moreover, the cyano dipole-dipolepairings combined with the H-bonding interactions contributed to atremendously increased lap shear strength of up to 7.18 MPa as wellas good energy dissipation and damping capacity. The rationally designeddual-cross-linked network strengthening mechanism reported here offersan important and universal strategy for significantly enhancing thecomprehensive properties of thermosets. Renewableraw feedstocks and the addition of green catalystsensure the sustainability of resins at the source of production andpart of the process.