Center for Sustainable Polymers

The permanent crosslinks of thermosets and elastomers provide excellent mechanical strength and solvent resistance, but hinder mending and recycling. When these materials are at the end of their useful life, they are discarded, incinerated, or ground for downgraded applications, resulting in significant environmental damage and financial loss.1 The ideal crosslink would be inert under service conditions, but would undergo dissociation or exchange when energy is applied (e.g. as heat, chemical reagents, or light). Many well-established reversible reactions (Diels–Alder, transesterification, transcarbamoylation, transamination) have been applied to create recyclable and mendable crosslinked thermosets and elastomers.