Effects of silane-modified nano-Al 2 O 3 on thermal and electrical properties of magnolol-based epoxy resin

Bio-based epoxy resins are gaining attention as renewable alternatives to diglycidyl ether of bisphenol A (DGEBA), yet their multifunctional performance remains insufficient for advanced engineering applications. In this study, 3-aminopropyltriethoxysilane (KH550)-functionalized Al 2 O 3 nanoparticles were incorporated into a magnolol-based epoxy resin (MAEP) to systematically enhance its thermal, mechanical and electrical properties. The rigid KH550-Al 2 O 3 nanoparticles effectively restrict the motion of the MAEP chain segments, leading to a glass transition temperature (T g ) of 148.06 °C at a filler content of 20 wt%, which is 17.65 °C higher than that of neat MAEP. Meanwhile, the homogeneous dispersion of nanofillers promotes efficient interfacial stress transfer, thereby increasing the tensile strength and tensile modulus to 55.55MPa and 1097.76 MPa, respectively, nearly doubling those of the neat MAEP. Furthermore, by restricting the mobility of the MAEP network and suppressing charge carrier transport, the MAEP nanocomposites containing 10 wt% KH550-Al 2 O 3 exhibit an alternating current (AC) breakdown strength of 54.96 kV/mm. Collectively, these findings highlight the potential of interfacial engineering using functionalized nanoparticles as a promising route to tailor the comprehensive performance of bio-based MAEP, offering valuable insights for the design of high-performance, bio-derived electrical insulating materials.