Faculty Sponsor's Department(s):
Polymer networks crosslinked with dynamic covalent bonds and prepared via additive manufacturing, or 3D-printing, are a promising subset of thermoset materials with applications in automation, architecture, and medicine. Room temperature-exchangeable dynamic covalent bonds have the potential to increase the interlayer strength of a 3D-printed material in situ, while also overcoming the impediments that permanently crosslinked materials display, such as the inability to be chemically modified post-manufacturing. The goal of this work is to create 3D-printed dynamic covalent networks containing both dynamic diallyl boronate (DABo) and static diallyl phthalate (DAP) monomers. We will prepare resin formulations that range from 0 to 25 mol% DABo to investigate the effect that the room temperature exchange of the dynamic DABo units has on these materials. The formulations will be used to 3D-print the elastomers, using a digital light processing (DLP) 3D-printer, which uses a 385 nm-light to cure the liquid resin in a layer-by-layer fashion. The networks will then be subjected to a post-print UV cure to ensure high conversion of the monomers. Notch tests will then be used to determine the fracture energy of the respective printed formulations, which will provide a mechanism to quantify the interlayer strength. Results from this work have the potential to introduce a method to further improve the interlayer adhesion in 3D-printed materials by using small amounts of room temperature-active dynamic crosslinks.