Microcapsule-Based Self-Healing in High Impact Polystyrene Composites for Additive Manufacturing

Polymer composites are widely used for various industrial applications due to their excellent mechanical properties. However, damage repair and replacement of polymer composites is costly and time consuming. Therefore, development of damage resistant and durable polymer composites is necessary. These materials are becoming increasingly popular due to their retention of mechanical properties after damage and associated cost savings. Also, with the rise of additive manufacturing technologies for polymer composite fabrication the extension of self-healing capabilities to additive manufacturing platforms is desirable. Self-healing polymer composites have the ability to intrinsically heal damage. This work extends microcapsule self-healing to additive manufacturing by demonstrating microcapsule survivability in compression molding and FDM 3D printing. We utilize polyurethane-urea formaldehyde (PU-UF) double walled microcapsules with ethyl phenylacetate (EPA) as the self-healing fluid and high impact polystyrene (HIPS) as the bulk polymer. Microcapsules are incorporated within compression molded HIPS and fusion deposition modelling 3D printed HIPS specimens. We demonstrate microcapsules survive both of these fabrication techniques. Flexure and fracture tests with and without microcapsules are then used to assess the impact of microcapsules on physical properties compared to virgin HIPS specimens, as well as the self-healing efficiency of the composites after fracture.