Abstract
The development of dynamic covalent chemistry opens the way to the design of materials able to be reprocessed by internal exchange reaction under thermal stimulus. Imine exchange differs from other exchange reactions by its relative low temperature of activation. In this study, amine-functionalized star-shaped PEG-PLA and aldehyde-functionalized hydroxyurethane modifier were combined to produce PEG-PLA/hydroxyurethane networks incorporating imine bonds. The thermal and mechanical properties of these new materials were evaluated as a function of the initial ratio of amine/aldehyde used during synthesis. Rheological analyses highlighted the dynamic behaviour of these vitrimers at moderate temperature (60-85 °C) and provided the flow activation energies. Additionally, the reprocessability of these PEG-PLA/hydroxyurethane vitrimers were assessed by comparing the material properties before reshaping and after three reprocessing cycles (1 ton, 1 h, 70 °C). Hence, these materials can easily be designed to satisfy a specific medical application without properties loss. This work opens the way to the development of a new generation of dynamic materials combining degradable PEG-PLA copolymers and hydroxyurethane modifiers, which could find application to shape medical devices on-demand under mild conditions.