Furan-derived Schiff base covalent adaptable thermosets with recyclability and anti-flammability

Conventional thermosetting polymers, mostly derived from nonrenewable petroleum resources, are not reprocessable and recyclable due to their highly cross-linked three-dimensional networks and face the disadvantage of high flammability. To solve these issues, in this study, we synthesized a novel Schiff base covalent adaptable thermoset from a furan-derived tri-aldehyde monomer (TMFP) and a furan-derived di-amine monomer (DFDA). The as-prepared TMFP-DFDA-Vitrimer exhibited superior anti-flammability with a high limiting oxygen index (LOI) of 35.0% and a UL-94 V-0 rating, which was attributed to the excellent charring ability. Additionally, TMFP-DFDA-Vitrimer could also be conveniently recycled by chemical decomposition under a mixed hydrochloric acid/tetrahydrofuran (HCl/THF) solution. After recycling for 5 times, the thermal, mechanical, and flame retardant properties of the recycled TMFP-DFDA-Vitrimer retained almost unchanged compared to the original one. This work provides a prime instance to develop advanced thermosetting polymers from abundant furan-based compounds.