Mountaki Stella Afroditi, Whitfield Richard, Liarou Evelina, Truong Nghia P, Anastasaki Athina
Laboratory of Polymeric Materials, Department of Materials, ETH Zurich, Zurich 8093, Switzerland.
Department of Chemistry, University of Warwick Library Road, Coventry CV4 7SH, U.K.
J Am Chem Soc. 2024 Jul 17;146(28):18848-18854. doi: 10.1021/jacs.4c05621. Epub 2024 Jul 3.
While oxygen-tolerant strategies have been overwhelmingly developed for controlled radical polymerizations, the low radical concentrations typically required for high monomer recovery render oxygen-tolerant solution depolymerizations particularly challenging. Here, an open-air atom transfer radical polymerization (ATRP) depolymerization is presented, whereby a small amount of a volatile cosolvent is introduced as a means to thoroughly remove oxygen. Ultrafast depolymerization (i.e., 2 min) could efficiently proceed in an open vessel, allowing a very high monomer retrieval to be achieved (i.e., ∼91% depolymerization efficiency), on par with that of the fully deoxygenated analogue. Oxygen probe studies combined with detailed depolymerization kinetics revealed the importance of the low-boiling point cosolvent in removing oxygen prior to the reaction, thus facilitating effective open-air depolymerization. The versatility of the methodology was demonstrated by performing reactions with a range of different ligands and at high polymer loadings (1 M monomer repeat unit concentration) without significantly compromising the yield. This approach provides a fully oxygen-tolerant, facile, and efficient route to chemically recycle ATRP-synthesized polymers, enabling exciting new applications.
虽然针对可控自由基聚合已经大量开发了耐氧策略，但高单体回收率通常所需的低自由基浓度使得耐氧溶液解聚极具挑战性。在此，提出了一种露天原子转移自由基聚合（ATRP）解聚方法，通过引入少量挥发性共溶剂作为彻底去除氧气的手段。超快解聚（即2分钟）可以在开放容器中高效进行，实现非常高的单体回收率（即约91%的解聚效率），与完全脱氧的类似物相当。氧探针研究结合详细的解聚动力学揭示了低沸点共溶剂在反应前去除氧气的重要性，从而促进了有效的露天解聚。通过在一系列不同配体以及高聚合物负载量（1 M单体重复单元浓度）下进行反应，证明了该方法的通用性，且产率没有显著降低。这种方法为化学回收ATRP合成的聚合物提供了一种完全耐氧、简便且高效的途径，从而实现令人兴奋的新应用。
