(181au) Microcapsule-Based Self-Healing for 3D Printing

Additive manufacturing technologies have seen a dramatic increase in both attention and industrial application driven by its mass customization, decreasing costs of 3D printing equipment, low waste generation, and overall progress in ease-of-use through software improvements. There are currently a limited (though growing) range of polymer materials available for 3D printing. Additionally, many of the polymer material options for 3D printing are not intrinsically recyclable, requiring disposal if they suffer any damage. Here, we aim to improve the lifetime of 3D printed polymeric objects through the incorporation of self-healing properties. Inspired by biological self-healing, in which a damage event triggers an autonomic healing response, microcapsules containing healing agents can be embedded into a host material. During a damage event these microcapsules rupture, release the healing agent and heal the surrounding material by polymerization, entanglement or cross-linking. We aim to synthesize microcapsules and leverage microcapsule shell wall chemistry to tune their properties to both withstand high shear stresses during 3D printing and promote the autonomic healing response after damage. 3D printable self-healing polymers will increase product shelf life, mechanical performance, and thereby improve material sustainability and long-term cost. Double shell wall polyurethane/poly(urea-formaldehyde) microcapsules are synthesized by in-situ polymerization. Microcapsules with both solvent and monomer core fluids are prepared to investigate both solvent-healing and monomer self-healing mechanisms. Microcapsules containing healing agents are either incorporated into the host polymer matrix or are coated onto 3D printing polymer filaments to create 3D printed objects capable of self-healing. Microcapsule survivability after 3D printing is evaluated via examination of the healing efficiency and mechanical strength of the fabricated 3D printed objects.