Controlled synthesis and closed-loop chemical recycling of biodegradable copolymers with composition-dependent properties  

作　　者：Yi-Teng Yan Gang Wu Si-Chong Chen Yu-Zhong Wang 

机构地区：[1]The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials(MoE),National Engineering Laboratory ofEco-Friendly Polymeric Materials(Sichuan),State Key Laboratory of Polymer Materials Engineering,College of Chemistry,Sichuan University,Chengdu 610064,China

出　　处：《Science China Chemistry》2022年第5期943-953,共11页中国科学（化学英文版）

基　　金：supported by the National Key R&D Program of China (2016YFC1100702);the National Natural Science Foundation of China (U19A2095);the Sichuan Science and Technology Program (2017SZDZX0015);the Fundamental Research Funds for the Central Universities。

摘　　要：The closed-loop recycling concept of the polymer wastes into building-block chemicals is attractive,but the closed-loop recycling of copolymers enabled by energy-efficient chemical recycling and cost-effective separations is still facing great challenges.Herein,for the first time,a one-pot sequential copolymerization of γ-butyrolactone(γ-BL) and p-dioxanone(PDO)using an economical ureas/alkoxides catalytic system is conducted to synthesize biodegradable and chemically recyclable poly-(γ-butyrolactone)-block-poly(p-dioxanone)(PγBL-b-PPDO) diblock copolymers with well-defined and controlled structures.The composition-dependent properties of PγBL-b-PPDO copolymers,including thermal properties and crystallization behavior,are investigated.The results show that the thermal stability and crystalline ability of PγBL are enhanced observably by introducing the PPDO block.Significantly,the PγBL-b-PPDO copolymers can be depolymerized efficiently into the corresponding co-monomers with a yield of over 95% by simply low-temperature pyrolysis under vacuum.Moreover,γ-BL and PDO monomers are selectively separated with an isolated purity of about 99% based on the difference in their physicochemical properties.Subsequently,their repolymerization is realized to obtain the copolymers with nearly identical structures and thermostability,demonstrating the closed-loop recycling of copolymers,i.e.,polymerization-depolymerization-repolymerization.This research provides important guidance for the design of novel sustainable polymers towards more efficient chemical recycling,separation and regeneration.

关 键 词：BIODEGRADABLE COPOLYESTER poly(p-dioxanone) tunable properties closed-loop chemical recycling 

分 类 号：TQ317[化学工程—高聚物工业]