Synthesis of Eugenol‐Derived Furanylbenzoxazine and Properties of Its Copolymer With Epoxy Resin

ABSTRACT To increase the toughness of epoxy resin, an allyl‐terminated furanylbenzoxazine (AFB) derived from eugenol was copolymerized with epoxy resin (E51). Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) analyses were used to examine the curing behavior of the blended resins. With increasing AFB content, the crosslinking density of the EP‐AFB resins decreases, while the residual carbon yield ( Y c ) of the epoxy resins after high‐temperature combustion in a nitrogen atmosphere increases. The Y c of EP‐4AFB increased from the initial 14.92% to 20.21%. In addition, appropriate concentration of AFB could be conducive to improving the mechanical properties. The flexural and impact strengths of EP‐1AFB resins were 3.5% and 81.3% higher than EP resins, respectively. The elongation at break and tensile strength of EP‐3AFB resins were 91.2% and 68.4% higher than EP resins, respectively. Furthermore, the addition of AFB significantly modified both adhesive (lap shear strength and peel strength) and dielectric properties of the epoxy resins.