High-Performance Dynamic Photo-Responsive Polymers With Superior Closed-Loop Recyclability

Abstract

Chemical recycling to monomer (CRM) provides an ideal solution for reducing plastic waste and achieving a circular polymer economy. Cyclopentene (CP) and its derivatives are representative molecules that exemplify an efficient CRM process under mild conditions. However, most CP-based polymers possess limited thermal and mechanical properties, constraining their potential applications. Herein, new CP-based polymers with superior thermo-mechanical properties and autonomous functions are proposed by integrating anthracene as a dynamic functional motif. Anthracenes not only serve as supramolecular cross-linkages through strong pi-pi interactions but also form stronger chemical ones under UVA light irradiation, enhancing thermo-mechanical properties. Furthermore, damage-reporting, self-healing, and local shape reprogramming capabilities are accomplished by utilizing the reversible nature of photodimerized anthracene. A mild and orthogonal depolymerization condition for the CP-based polymers facilitates efficient monomer recovery even from mixed plastic wastes. This work presents a simple yet effective strategy to expand the usability of chemically recyclable polymers and contribute to a closed-loop polymer economy. An all-around monomer, anthracene-substituted cyclopentene, is proposed for producing chemically recyclable polymers with damage-reporting and self-healing capabilities by combining two orthogonal reversible chemistries. The polymers exhibit comparable hardness and elastic modulus to engineering plastics, along with multiple shape programming behaviors. Excellent chemical recyclability to monomers is also accomplished, even from mixed plastic wastes. image