Photodegradable Dynamic Polyurethane Networks via Dithioacetals

Cross-linked polymer networks fabricated with renewable resources are being actively sought for tackling the resource crisis. Meanwhile, dynamic networks with cleavable groups further promote recycling and degradation. Herein, a vanillin-derived trifunctional compound containing a dithioacetal moiety was found to be an efficient cross-linker for making polyurethane networks (PUNs) with coexisting dynamic dithioacetal and phenolic carbamate groups. The dual-dynamic PUNs were featured with faster stress relaxation over monodynamic PUNs, good stability in acidic environments, and thermally promoted recyclability. Moreover, photocleavage of the dithioacetal groups was realized under blue light (460 nm) to trigger the network degradation. This work represents an appealing molecular design to realize photodegradable dynamic networks via introducing dithioacetals, which could potentially be degraded under different wavelengths.