A novel bio-based trifunctional phthalonitrile monomer: Synthesis, curing behavior, thermal properties

A bio-based triphenol compound (GVT) was prepared using vanillin and guaiacol from biomass as starting materials. Then, 4-nitrophthalonitrile was used to obtain a new bio-based trifunctional phthalonitrile monomer (GVTP) through nucleophilic substitution reaction in a green solvent. The successful preparation of GVT and GVTP was proved by hydrogen and carbon nuclear magnetic resonance ( 1 H NMR, 13 C NMR) and Fourier transform infrared spectroscopy (FT-IR). 4-(4-aminophenoxy)phthalonitrile (APPN) was chosen as the curing agent. Tests were carried out using FT-IR, differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), and rheometer. The results showed that the prepolymer had a wide processing window and low melt viscosity at 220.5 ℃ (0.404 Pa·s). The cured resin had a high glass transition temperature ( T g ) (402 °C). When the post-curing temperature is 375 °C, the temperatures at 5 % weight loss ( T 5 ) are 521 °C. This research offers an environmentally friendly method for effectively using bio-based aldehydes and bio monophenols, and the prepared resin offers the benefits of carbon reduction and renewability.