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

ABSTRACT This study reports the synthesis of a eugenol‐derived benzoxazine resin (AEM) from 3‐ethynylaniline and bio‐based eugenol, and its structural characterization using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance ( 1 HNMR). Subsequently, the AEM resin was copolymerized with bisphenol‐type epoxy resin (E51) in varying proportions to form an EP‐AEM modified resin system, whose processability, dynamic thermomechanical properties, thermal stability, dielectric properties, mechanical properties, and adhesion performance were investigated. The flexural strength, tensile strength, and elongation at break of EP‐2AEM resins were 7.6%, 53.7%, and 41.2% higher than EP resins, respectively. In particular, AEM markedly increases the residual carbon yield ( Y c ) after high‐temperature combustion in a nitrogen atmosphere, and this improvement becomes more pronounced as the AEM concentration increases. Compared with neat EP resin (14.92%), EP‐4AEM resin exhibits a significantly higher value (21.59%). The high‐temperature adhesion strength of EP‐2AEM increases by 51.5%. Moreover, EP‐4AEM shows the lowest dielectric constant (2.49) and dielectric loss tangent (0.022).