Biobased Polystyrene Vitrimers for Thermoset Circularity

Thermoset polymers, known for their robust thermomechanical and chemical durability, suffer from poor recyclability due to their covalent cross-linking. This study explores the tunability of covalent adaptable networks (CANs), specifically prepolymer-derived vitrimers, which offer both durability and recyclability through dynamic covalent cross-links. By utilizing biobased vanillin methacrylate (VnMA) and Priamine cross-linkers, we synthesized polystyrene (PS) vitrimers with readily tunable viscoelastic properties. The vanillin-derived PS copolymer was cross-linked with varying equivalents of Priamine to favor different exchange mechanisms: transamination for rapid processability and metathesis for enhanced dimensional stability. Extending the prepolymer chain length above the entanglement threshold also introduced physical cross-links that significantly improved creep resistance. Our findings highlight a versatile approach for creating biobased, reprocessable thermosets with high thermomechanical performance. The incorporation of primary chain entanglement and the ability to tune exchange mechanisms offer a promising pathway for sustainable and durable polymer materials suitable for various applications. This methodology enhances the recyclability and sustainability of PS-based materials, broadening their commercial utility.