Multi-recyclable cross-linked supramolecular polyurea materials

Abstract

Covalent thermosets generally exhibit robust mechanical properties and dimensional stability, but suffer from fragility, intractability and lack of recyclability. After the end-of-life usage, most thermosets are discarded, leading to severe wastes of resources and causing environmental problems. Recently, Xu, Zhang and co-workers proposed a new strategy of incorporating low-content noncovalent bonds into polymer main chains to construct tough and multi-recyclable cross-linked supramolecular polyureas. The polyureas were prepared via the copolymerization of quadruple hydrogen-bonded supramonomers and covalent monomers/crosslinkers. It was shown that the remarkable mechanical properties of covalent cross-linked polymers and excellent multiple recyclability of supramolecular polymers were well combined in the cross-linked supramolecular polyureas. The molecular design is simple but elegant. It is anticipated that the similar methodology can be used for making various cross-linked supramolecular polymer materials with superior recyclability and mechanical properties, thus providing a new and general strategy for the preparation of reprocessible and recyclable cross-linked materials. © 2020 Science Press. All rights reserved.