Large-Deformed Reshaping of Brittle Thermosets via Mechanochemical Programming

Highly crosslinked thermosets have found broad applications due to their excellent mechanical performance and chemical stability. But it is extremely challenging to reprocess brittle thermosets due to their permanently crosslinked polymer networks. In this work, a mechanochemical programming strategy is proposed to realize rapid and large-deformed reshaping of brittle thermosets. Incorporating the bond exchange reaction-induced stress relaxation into the viscoelastic theory, the relation between the stress relaxation factor of brittle thermosets and the shape retention ratio of reshaped beams is theoretically predicted. Based on the theoretical relation, a partial shape retention method for reshaping brittle thermosets is proposed, which can considerably reduce the time cost. Also, a stepwise relaxation method is proposed to achieve accumulated plastic deformation that breaks through the elastic break strain of brittle thermosets, which realizes large-deformed reshaping. Finite element calculation facilitates the reshaping of complex structures by guiding the implementation of stepwise programming deformation. Overall, this work enables efficient and flexible reshaping of brittle thermosets, paving the way for manufacturing complex structures.