Mechanical and Dielectric Property Enhancement of Epoxy Resins With Eugenol Derived Allyl Benzoxazine

A bio-based allyl-terminated benzoxazine (AMP) was copolymerized with epoxy resins (E51) to enhance the toughness of epoxy resins. The curing behavior of the blended resins was investigated using differential scanning calorimetry (DSC) analysis and Fourier transform infrared (FTIR) spectroscopy. The crosslinking density and gel content of EP-AMP resins were decreased with the increasing AMP content. AMP significantly improved the residual carbon yield ( Y c ) of epoxy resins following high-temperature combustion in N 2 atmosphere, with enhancements correlating positively with AMP concentration. Compared with the value of EP resins (14.92%), the value of EP-4AMP resins (19.41%) was well increased. The mechanical properties (including flexural, impact, and tensile tests) were evaluated, revealing substantial improvements. The flexural strength, tensile strength, and elongation at break of EP-3AMP resins were 11.7%, 104.8%, and 67.6% higher than EP resins, respectively. The impact strength of EP-2AMP resins was 66.9% higher than EP resins. Furthermore, the incorporation of AMP markedly modified both adhesive (lap shear strength and peel strength) and dielectric properties of the epoxy resins.