Amino Silane-Enhanced Biobased Isovanillin Epoxy Matrices with Excellent Thermal and Mechanical Performance

To establish sustainable and functional thermosetting resin, a isovanillin-derived oxiran-2-ylmethyl 4-methoxy-3-(oxiran-2-ylmethoxy) benzoate (OYMB) was initially synthesized and cured by aliphatic amino silane N-[3-(trimethoxysilyl) propyl] ethylenediamine (NED) and N-[3-(trimethoxysilyl)propyl]-N′-(2-aminoethyl) ethylenediamine (NNED), respectively. The resins were successively investigated in terms of thermal and mechanical properties and so forth. Results indicated that the combination of the OYMB with NED or NNED endowed networks with excellent thermal properties (T_d5 > 300 °C, and T_d30 > 400 °C) and high char residues (R₇₀₀, up to 55.1%), as well as significantly enhanced impact strength (up to 25.74 KJ/m²). Furthermore, compared with the diglycidyl ether of bisphenol A (DGEBA) analogues, the OYMB-derived networks also showed low flammable properties, wherein no soot deposits occurred during the combustion. Interestingly, no dripping occurred for both NED and NNED-cured networks. In addition, the highly improved impact strength of such networks will allow the reinforcement of composites in mechanics. It offers a useful reference to dealing with the melt dripping issue in other polymers. Notably, it was also proved that the resins possessed harmful light blocking property in UV bands and blue light range in the optical performance. Therefore, those properties will further promote their applications in composite materials and advanced materials.