A novel bio-based phthalonitrile resin derived from catechin: synthesis and comparison of curing behavior with petroleum-based counterpart

The development of bio-based thermosetting resins with good thermal stability can potentially afford sustainable polymers as replacements for petroleum-based polymers. We report a practical route to a novel catechin-based phthalonitrile resin precursor (CA-Ph), which contains free phenolic hydroxyl groups that result in ‘self-curing’ at elevated temperatures to afford a thermostable polymer. Comparison of the performance of this CA-Ph resin with that of a conventional petroleum-based bisphenol A phthalonitrile resin (BPA-Ph; containing 5 wt% of the curing agent 4,4′-diaminodiphenylsulfone) revealed that CA-Ph exhibits a lower melting point and curing temperature. Cured CA-Ph resin retains 95% of its weight at 520 °C under a nitrogen atmosphere, which compares favorably with results obtained for BPA-Ph resin that retains 95% of its weight at a lower temperature of 484 °C. Kinetic results indicated that the curing reactions of both CA-Ph and BPA-Ph systems follow an autocatalytic mechanism. These results suggest that catechin is a useful bio-based feedstock for the preparation of self-curing and thermally stable phthalonitrile resins for advanced technological applications. © 2017 Society of Chemical Industry