Chemical transformation of polyurethane into valuable polymers.

Abstract

Polyurethanes are an important class of synthetic polymers, widely used in a variety of applications ranging from everyday items to advanced tools in societal infrastructure. Their inherent cross-linked structure imparts exceptional durability and flexibility, yet this also complicates their degradation and recycling. Here we report a heterogeneous catalytic process that combines methanolysis and hydrogenation with a CO₂/H₂ reaction medium, effectively breaking down PU waste consisting of urethane and ester bonds into valuable intermediates like aromatic diamines and lactones. These intermediates are then converted into functional polymers: polyimide (PI), noted for its exceptional thermal and electrical insulation, and polylactone (P(BL-co-CL)), a biodegradable alternative to traditional plastics. Both polymers exhibit enhanced performance compared to existing commercial products. This approach not only contributes to the valorization of plastic waste but also opens new avenues for the creation of high-performance materials.