Chemical recycling of post-consumer PET into high-performance polymer aerogels

Abstract

Chemical recycling is an indispensable pathway for the sustainable disposal of post-consumer polyethylene terephthalate (PET). However, it faces significant challenges in terms of cumbersome separation and purification steps. Herein, we propose a chemical upcycling route that transforms post-consumer PET into organic aerogels. Benefiting from the well-designed symmetrical di-vanillin terephthalate structure, the resulting dialdehyde intermediate can be easily purified by recrystallization, eliminating the need for laborious separation steps. Furthermore, the obtained intermediate undergoes aldimine condensation with various amines, preparing polyimine-type organic aerogels. These aerogels exhibit excellent mechanical strength and thermal insulation capabilities, demonstrating potential as building insulation materials. Notably, these aerogels exhibit outstanding recyclability under acidic conditions at room temperature, displaying high yields and purities of recovered monomers, even when mixed with different commodity plastics. This work provides a “waste to wealth” strategy, using low-cost PET waste to construct closed-loop recyclable polymer aerogels, combining feasibility, economy, and sustainability.