We discovered that polyhydroxyurethane (PHU) networks synthesized in the presence of a catalyst from five-membered cyclic carbonates are intrinsically reprocessable with full property recovery via transcarbamoylation exchange reactions and reversible cyclic carbonate aminolysis. Through a judicious choice of monomers, we demonstrated that PHU networks can be recycled multiple times with full property retention. The presence of reversible reactions in addition to exchange reactions in PHU network reprocessing should spur reconsideration of the underlying reprocessing chemistries associated with some dynamic covalent polymer networks which have been ascribed solely to exchange reactions. With excellent reprocessability, this synthetic framework also serves as a sustainable non-isocyanate-based alternative to traditional polyurethane (PU) networks.
Bibliographical noteFunding Information:
This work made use of central facilities supported by the MRSEC program of the National Science Foundation (DMR-1121262) at the Northwestern University Materials Research Science and Engineering Center as well as facilities supported by Northwestern University at the Integrated Molecular Structure Education and Research Center (IMSERC). We also acknowledge support of Northwestern University via discretionary funds associated with a Walter P. Murphy Professorship (J. M. T.), an ISEN Fellowship (L. L.), and a Terminal Year Fellowship (K. J.).