Stereolithography 3D Printing of Microcapsule Catalyst-Based Self-Healing Composites

Polymer-based components manufactured by stereolithography-based (SLA) three-dimensional (3D) printing tend to show relatively poor mechanical strength compared to polymer-based components fabricated by conventional methods such as compression molding. Some of this difference is related to the thermoset nature of typical SLA 3D-printed materials, where high cross-linking density and brittle material behavior can result in catastrophic material failure, limiting the life span of SLA 3D-printed composite materials. Previous studies have investigated potential techniques for improving the mechanical strength of SLA 3D-printed polymer components, such as the addition of various strengthening fillers; however, a few studies have investigated the incorporation of self-healing materials for SLA 3D printing to extend material lifetimes. In this study, we investigate the use of a microcapsule catalyst self-healing system in conjunction with commercially available photocurable resin toward increasing SLA 3D-printed specimen lifetime and material sustainability. Microcapsules filled with healing fluids are synthesized using in situ interfacial polymerization and dispersed in commercial resin prior to SLA 3D printing of self-healing composite specimens. The ability of these microcapsules to survive the SLA 3D printing process intact is demonstrated, and X-ray nano-computed tomography (X-ray Nano-CT) imaging shows microcapsules to be distributed throughout printed specimens. The self-healing behavior of these SLA 3D-printed composite materials is evaluated via quantification of mechanical properties, and healing efficiency. Overall, this is a facile and promising approach for the incorporation of self-healing behavior into SLA 3D printing resins.