Polycarbonate Upcycling Into Block Copolymers via Transcarbonation: Influence of the Catalyst on the Microstructure

The upcycling of plastics into high‐value materials has emerged as a promising strategy to handle plastic waste. The production of block copolymers is an interesting route. This can be done by polymer / polymer interchange reaction, where telechelic polymers can play a pivotal role. The work describes the upcycling of aromatic polycarbonate (PC‐BPA) into PC‐BPA‐Polybutadiene (PBd) multiblock copolymers. The copolymers are synthesized via a transcarbonation reaction between hydroxytelechelic polybutadiene (PBd) and PC‐BPA using N‐heterocyclic bases as catalysts. A deep analysis of their microstructure is realized by NMR. The true formation of the copolymers is confirmed by DOSY experiments. It is shown that the nature of the catalyst strongly influences the microstructure of the resulting copolymers: TBD (1,5,7‐ triazabicyclo[4.4.0]dec‐5‐ene) provides high conversions and yields multiblock copolymers, while DMAP (4‐dimethylaminopyridine) affords higher molecular weights materials with lower conversions and predominantly diblock structures. The PBd content of the latter copolymers is much lower than that of the former. As consequence, the thermal properties also differ. This work provides, to the best of our knowledge, the first report of PC‐BPA/PBd multiblock copolymers.