Synthesis and characterization of epoxy resins from fast pyrolysis bio-oil

Fast pyrolysis bio-oil was used to replace phenol up to 50 wt% to synthesize bionovolac resin. A glycidylation reaction was employed for epoxidizing novolac, bionovolac, fast pyrolysis bio-oil and α-resorcylic acid. Gas chromatography–mass spectroscopy was used to observe available compounds in the bio-oil, whereas Fourier transform infrared and phosphorus-31 (³¹P) nuclear magnetic resonance techniques were used for the characterization of the resulting resins. Epoxy resins were cross-linked by polyaddition reaction with the polyetheramine hardener Jeffamine T-403 at elevated temperatures. The thermal and thermomechanical properties of cured thermosets were measured by differential scanning calorimetry and dynamic mechanical analysis, respectively. The glass transition temperatures and moduli of novolac-based cross-linked systems were found to be superior to those of epoxy resins without novolacs. Additionally, Soxhlet extraction and scanning electron microscopy were performed to characterize solvent resistance and morphology, respectively. The incorporation of α-resorcylic acid-based epoxy enhanced the properties of cured polymers. The preparation of bio-based epoxy–novolac thermoset networks resulted in reduced consumption of petroleum-based chemicals.