Fracture-Initiated Hybrid Adhesives for Self-Repairing Composites

Novel fracture-initiated adhesive materials are proposed for fabricating thermally stable, polymer matrix composites with the ability to repair themselves after sustaining structural damage. The proposed research explores the feasibility of modifyingconventional thermoset resins with microencapsulated hybrid monomers that upon matrix fracture, spread to the damaged area and stabilize the structure through ambient temperature polymerization. The main objective is to develop an easily processed resinsystem with strong adhesion to reinforcing fibers, high thermal stability, robust reactivity over a wide temperature range, and the ability to recover mechanical properties after being damaged. The proposed microencapsulated hybrid monomers cure by acombination of chemical processes by contact with matrix-embedded low cost catalysts. The resulting repair resins will exhibit equivalent thermal stability to the original matrix resin system. In the proposed study, the candidate materials for theseresin repair additives will be identified, a new type of inorganic-organic hybrid monomer synthesized, structure-property profiles determined and the ability to cure into useful materials by fracture-induced initiation demonstrated. Mechanical propertiesof candidate composite specimens and controls with glass and graphite fiber-reinforcements will be measured before and after impact-induced damage and compared. Procedures for applying this technology to aerospace-grade composites will be prepared. Thebenefits of an easy-to-process, impact resistant composite having the ability to repair itself after sustaining damage include higher survivability, excellent environmental durability, improved mission readiness and lower maintenance costs. Potentialcommercial applications lie in the manufacture of structural aerospace components for both military and civilian markets as well as for automotive applications.