Constructing recyclable biomass-derived thermosetting polymers via a solvent-free and catalyst-free Knoevenagel condensation reaction

Abstract

The extensive utilization of thermosetting polymers has prompted growing environmental concerns due to their non-recyclability and resource depletion. To address these challenges, the development of eco-friendly synthetic strategies for creating recyclable thermosetting polymers is imperative. Herein, we developed a solvent-free and catalyst-free synthesis approach to prepare recyclable biomass-derived thermosetting polymers using the dynamic Knoevenagel condensation (KC) reaction. We demonstrated that the dynamic exchange of CC bonds could occur via the KC reaction at 110 °C without the need for solvents or catalysts. The thermosetting polymer BFMD-PCLT was then synthesized via the solvent-free and catalyst-free KC reaction. The resulting BFMD-PCLT exhibited an elongation at break of 184%, a tensile strength of 3.6 MPa, and exceptional fatigue resistance (withstanding ≥500 stretching cycles). Furthermore, BFMD-PCLT demonstrated high thermal stability (up to 275 °C) alongside excellent reprocessability and chemical recyclability. Overall, this research provides an eco-friendly, facile, and sustainable approach for creating recyclable biomass-derived thermosetting polymers.