Biobased Polystyrene Vitrimers for Thermoset Circularity

Thermoset\npolymers, known for their robust thermomechanical and\nchemical durability, suffer from poor recyclability due to their covalent\ncross-linking. This study explores the tunability of covalent adaptable\nnetworks (CANs), specifically prepolymer-derived vitrimers, which\noffer both durability and recyclability through dynamic covalent cross-links.\nBy utilizing biobased vanillin methacrylate (VnMA) and Priamine cross-linkers,\nwe synthesized polystyrene (PS) vitrimers with readily tunable viscoelastic\nproperties. The vanillin-derived PS copolymer was cross-linked with\nvarying equivalents of Priamine to favor different exchange mechanisms:\ntransamination for rapid processability and metathesis for enhanced\ndimensional stability. Extending the prepolymer chain length above\nthe entanglement threshold also introduced physical cross-links that\nsignificantly improved creep resistance. Our findings highlight a\nversatile approach for creating biobased, reprocessable thermosets\nwith high thermomechanical performance. The incorporation of primary\nchain entanglement and the ability to tune exchange mechanisms offer\na promising pathway for sustainable and durable polymer materials\nsuitable for various applications. This methodology enhances the recyclability\nand sustainability of PS-based materials, broadening their commercial\nutility.