The effect of the vanillin-derived Si-containing compound on the curing behavior, thermal and mechanical properties of bismaleimide resins

Bismaleimide (BMI) resins is widely used in the aerospace field because of its excellent properties, but its poor toughness limits the possibility of its application in a wider range of fields. Therefore, a novel bio-compound, 4-(allyloxy)-3-methoxy-N-(3-(triethoxysilyl)propyl)benzamide (AMTPM), was designed and synthesized from renewable vanillin, which has Schiff-base structure, silico-oxygen bond structure, and allyl structure. The chemical structure of AMTPM has been characterized and validated by Fourier transform infrared (FTIR) and hydrogen nuclear magnetic resonance ( 1 H NMR). It was found that the addition of AMTPM can effectively promote the curing behavior of BD resins (BMI and diallyl bisphenol A (DBA) was mixed and cured at the ratio of 1:0.87, named BD resins). AMTPM can affect the thermal stability and improve the mechanical properties of BD-AMTPM resins (BD resins modified by AMTPM in different addition), and the detailed discussion was conducted. With the increase of AMTPM content, the thermal stability of BD-AMTPM resins was deteriorated while the residual weight percentage at 800°C ( Y c ) was increased. When the content of AMTPM reached 12 wt%, the results showed that Y c achieved the values at a magnitude of 37.57%. Meanwhile, the glass transition temperature ( T g ) achieved 320°C. Among the BD-AMTPM resins system, the BD-6 wt% AMTPM has the best toughness and mechanical properties. The impact strength was increased by 29.2%, the tensile strength was increased by 22.1% and the elongation at break was increased by 44%. The fracture morphology of BD-AMTPM resins was also studied by scanning electron microscopy (SEM) to support the mechanical experimental conclusions. This study provides a more environmentally friendly and convenient modifier, which is of great significance for expanding the application of bismaleimide resin. Highlights A bio-based modifying agent (AMTPM) was designed and successfully synthesized. AMTPM has both Si-O and Schiff-base structures. AMTPM can effectively improve the toughness of BD-AMTPM resins through impact and tensile tests.