Synthesis and characterization of novel epoxy resins from pyrolysis bio-oil as a curing agent of bio-oil phenol glyoxal novolac resin

The synthesis of novel bio-based epoxy resin (BOE) from beechwood pyrolysis oil and epichlorohydrin was carried out and its chemical structure was confirmed by FT-IR, GPC, and ¹H-NMR spectroscopy. The combination of fractional condensation and water extraction methods is proposed to obtain phenolic compounds from crude pyrolysis oil which has a complex composition with over 400 chemical compounds. In this work, a novelty is a fact that the synthesized BOE gradually replaces bisphenol A diglycidyl ether (DGEBA) equivalent (0-100%) to cure bio-oil based glyoxal novolac resin (BPG). The kinetic parameters of the curing reaction with model-free methods (Kissinger and Flynn–Wall–Ozawa methods) using data obtained from Differential Scanning Calorimeter (DSC). Incorporating BOE resin allowed to obtain a lower curing initial temperature, peak temperature, and activation energy compared to use DGEBA. this phenomenon becomes more significant when the BOE content increases. The physicochemical and thermal properties of the BOE and DGEBA cured BPG resins were analyzed and compared. These results indicate the water-insoluble fraction of condensate pyrolysis oil has the potential to synthesis high-performance sustainable biobased epoxy resins and also demonstrate the advantage of using the biobased epoxy resins to effectively replace DGEBA.