Among various recycling technologies developed, upcycling by catalytic depolymerization to monomers and small molecules is an attractive form of chemical recycling assuring an incentivize large-scale valorization of plastic wastes. A model polyester/polycarbonate block copolymer, cis-(exo,exo)-poly(cyclohexene carbonate/norbornene anhydride)-b-poly(cyclohexene carbonate) (poly(CHO/NA)-b-PCHC), undergoes preferable depolymerization under 4-dimethylaminopyridine (DMAP)/CHO organocatalytic system in light of the diverse degradablity of PCHC and poly(CHO/NA) block accompanying configuration transformation. The degradation is proceeded in three distinct steps: i.e. the PCHC block depolymerizes first, subsequently the PCHC moieties associated with poly(CHO/NA) block degrades, and then poly(CHO/NA) block decomposes. A stereochemical transformation of poly(CHO/NA) block from cis to trans is occurred during the whole degradation stage. The degradation of PCHC block and the configurational transformation of poly(CHO/NA) can be switched ?on/off? by simply altering the depolymerization atmosphere from argon to CO2. The systematic degradation data collected here can be used for the upcycling of polyester-block-polycarbonate.

» Author: Huining Ding, Xianmin Wu, Bing Han, Kening Guo, Zhongyu Duan, Binyuan Liu, Il Kim

» Publication Date: 01/09/2022

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