Development of Advanced Bio Thermoset Polymers from Sustainable Resources

Among the abundant molecules in nature, one has remained relatively underexplored in the domain of bio-based thermosets. In line with the pursuit of sustainability, we present the successful synthesis of a novel bio-based thermoset monomer (designated as Q-Ph) based on a naturally occurring flavonoid molecule, quercetin (Q). This synthesis involved a nitro displacement reaction with 4-nitrophthalonitrile. Structural confirmation of Q-Ph was achieved using hydrogen and carbon nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy (FTIR), and elemental analysis. Curing characteristics were assessed using differential scanning calorimetry, which indicated lower curing and polymerization temperatures compared to petroleum-based counterparts. Polymerization was further examined via temperature-dependent FTIR. Notably, the synthesized resin displayed superior performance, suggesting an autocatalytic curing mechanism. These findings highlight the potential of the developed phthalonitrile (PN) thermosets as a sustainable alternative to petrochemicals, particularly in high-performance applications.