Hydrogen Bonding-Rich Bio-Benzoxazine Resin Provides High-Performance Thermosets and Ultrahigh-Performance Composites

Producing thermosetting polymers using natural renewable resources has attracted great attention due to the requirement of sustainable development for human beings. Herein, we represent our design of a novel biobased thermosetting resin (KAE-fa) containing a polymerizable oxazine ring and a furan group derived from renewable kaempferol and furfurylamine. The distinctive presence of rich intra- and intermolecular hydrogen bonds within KAE-fa imparts it with thermal latent polymerization characteristic, long shelf life, and exceptional high performance of its resulting polybenzoxazine. Notably, the resulting thermoset, poly(KAE-fa), demonstrates a substantially high glass transition temperature (T-g) of 304 degrees C, an impressively elevated char yield (in N-2) of 63%, and an extraordinarily low heat release capacity of 10.12 J<middle dot>g(-1)<middle dot>K-1. In addition, KAE-fa has also been utilized to fabricate a carbon fiber-reinforced composite [CF/poly(KAE-fa)]. Employing this newly obtained high-performance bioresin as the matrix, CF/poly(KAE-fa) exhibits a remarkable property enhancement. For instance, CF/poly(KAE-fa) shows 108, 28, and 82.7% increases in T-g, tensile strength, and Young's modules (room temperature), respectively, compared with the carbon fiber-reinforced BA-a composite [CF/poly(BA-a)]. These advantages underscore the great potential of using renewable bioresins for developing both high-performance thermosets and composites with key applications spanning from transportation to aerospace.