Synthesis and Characterization of Epoxidized Beechwood Pyrolysis Bio-Oil as a Curing Agent of Bio-Based Novolac Resin

A bio-oil-based epoxy (BOE) resin was synthesized using phenolic compounds from beechwood pyrolysis oil. These compounds were separated from crude pyrolysis oil by coupling two methods: fractional condensation and water extraction. The chemical structure of the BOE resin was characterized by NMR and FTIR analyses. BOE resin was used as a curing agent of bio-oil glyoxal novolac (BOG) resin to gradually replace bisphenol A diglycidyl ether (DGEBA). The thermal properties of cured resins and kinetic parameters of the curing reaction using differential scanning calorimetry (DSC) were discussed. Incorporating the BOE resin resulted in a lower curing temperature and activation energy compared to using DGEBA. These results indicate that the water-insoluble fraction of pyrolysis oil condensate can potentially be used to synthesize high-thermal performance and sustainable epoxidized pyrolysis bio-oil resins and also demonstrate its application as a curing agent of bio-oil glyoxal novolac (BOG) resin.