Self-promoted curing phthalonitrile with high glass transition temperature for advanced composites

A novel self-promoted curing phthalonitrile monomer was synthesized via substitution reaction of 4-nitrophthalonitrile and 3-aminophenol at the presence of K₂CO₃ in the dimethylsulfoxide solvent. The phthalonitrile was characterized by Fourier transform infrared spectra, nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimetry, dynamic rheological analysis and thermal gravimetric analysis. The phthalonitrile monomer can be thermally polymerized with self-promoted curing behaviors. The prepolymerization reaction of the phthalonitrile prepolymer was investigated and the phthalonitrile prepolymer exhibited the desirable processing feature. With the curing process of low curing temperature and short curing time, the cured polymers exhibited high glass transition temperatures (241–270 °C) and excellent thermal stabilities with the 5 % weight loss temperature (395–441 °C). The novel phthalonitrile can be a good candidate as matrix for high performance polymeric materials.