Closed-loop chemical recycling of cross-linked polymeric materials based on reversible amidation chemistry

• Published in: Nature communications Vol. 13; no. 1; p. 7595
• Main Authors: Qin, Bo, Liu, Siyuan, Huang, Zehuan, Zeng, Lingda, Xu, Jiang-Fei, Zhang, Xi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.12.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 140/58; 639/301/923/1028; 639/638/298/923/1028; 639/638/455/941; Ambient temperature; Amines; Anhydrides; Aqueous solutions; Chemical bonds; Chemical recycling; Closed loops; Closed-loop recycling; Crosslinking; Depolymerization; Design; Elastomers; Humanities and Social Sciences; Maleic acid; Maleic Anhydrides - chemistry; Mechanical properties; Monomers; multidisciplinary; Plastics; Polymers; Polymers - chemistry; Recyclability; Recycling; Science; Science (multidisciplinary); Sustainable materials; Tensile Strength
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-35365-4

Closed-loop chemical recycling provides a solution to the end-of-use problem of synthetic polymers. However, it remains a major challenge to design dynamic bonds, capable of effective bonding and reversible cleaving, for preparing chemically recyclable cross-linked polymers. Herein, we report a dynamic maleic acid tertiary amide bond based upon reversible amidation reaction between maleic anhydrides and secondary amines. This dynamic bond allows for the construction of polymer networks with tailorable and robust mechanical properties, covering strong elastomers with a tensile strength of 22.3 MPa and rigid plastics with a yield strength of 38.3 MPa. Impressively, these robust polymeric materials can be completely depolymerized in an acidic aqueous solution at ambient temperature, leading to efficient monomer recovery with >94% separation yields. Meanwhile, the recovered monomers can be used to remanufacture cross-linked polymeric materials without losing their original mechanical performance. This work unveils a general approach to design polymer networks with tunable mechanical performance and closed-loop recyclability, which will open a new avenue for sustainable polymeric materials. Closed-loop chemical recycling provides a solution to the end-of-use problem of synthetic polymers but the design of dynamic bonds for preparing chemically recyclable cross-linked polymers remains challenging. Here, the authors report a dynamic reversible amidation reaction between maleic anhydrides and secondary amines.