Precision synthesis and closed-loop recycling of ultrahigh-molar-mass cyclic polymers

The precision synthesis of cyclic polymers with ultrahigh molar mass (UHMM) and circularity is challenging. Now, a method that involves superbase-mediated living linear-chain growth followed by macromolecular cyclization triggered by protic quenching enables the on-demand production of UHMM cyclic polymers with a narrow dispersity and closed-loop chemical recyclability.