Fracture-Initiated Hybrid Adhesives for Self-Repairing Composites

"Novel fracture-initiated resin additives are proposed for fabricating polymer matrix composites with the ability to self-repair after sustaining structural damage. The Phase I objective was to develop an easily processed resin system with strong adhesionto reinforcing fibers, high thermal stability, robust reactivity over a wide temperature range, and the ability to recover mechanical properties after being damaged. The proposed repair resin additives are activated by fracture-induced strain and act toarrest propagating matrix cracks and partially self-repair crack damage. The resulting repair resins will exhibit equivalent thermal stability to the original matrix resin system. In the proposed study, the candidate materials for these resin repairadditives will be identified synthesized, and structure-property profiles determined. The ability of the phase-segregated resins to transform by fracture-induced strain into crack-blunting toughened materials will be demonstrated. The proposed Phase IIprogram would extend the benefits of novel phase-segregated resin systems to advanced composites produced by cost-efficient manufacturing methods. Mechanical properties of candidate composite specimens and controls with glass and graphitefiber-reinforcements will be measured before and after impact-induced damage and compared. Procedures for applying this technology to the fabrication of aerospace composite structures will be demonstrate