Room Temperature Synthesis of a Novel Quinolinoxazine, Polymerization and Flammability Studies

A novel quinoline-containing benzoxazine resin, <b>8HQ-fa</b>, has been successfully synthesized at room temperature using sustainable raw materials, such as 8-hydroxyquinoline and furfurylamine as the phenol and amine source, respectively. The chemical structure of the hereinafter referred to as quinolinoxazine is fully characterized by Fourier transform infrared spectroscopy (FT-IR), ¹H and ¹³C nuclear magnetic resonance spectroscopy (NMR), as well as by 2D ¹H-¹H nuclear Overhauser effect spectroscopy (NOESY) and ¹H-¹³C heteronuclear multiple quantum correlation (HMQC) NMR. Thermal properties and polymerization behavior of the monomer are studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The resulting polymer is also characterized in terms of its thermal and fire-related properties by DSC, TGA, and microscale combustion calorimetry (MCC). The resulting thermoset, <b>poly(8HQ-fa)</b>, presents good thermal stability as evidenced by its <i>T</i>_g (201 °C), <i>T</i>_d5 and <i>T</i>_d10 (307 and 351 °C, respectively), and char yield (42%), and low flammability as determined by the LOI, heat release capacity, and total heat released values (34.3, 143 J/gK, and 10.8 kJ/g, respectively), making it a self-extinguishing thermoset. The combination of properties and advantages in the synthesis of <b>8HQ-fa</b>, accompanied by a low polymerization temperature, suggests its great potential in the field of high-performance polymers.