Thermally Initiated Self Healing Polymer Nanocomposites

High performance epoxy-fiber based composite materials are needed to maintain Air Theater Superiority over the modern battlefield. Lightweight high strength materials have greatly advanced the capabilities of jet aircraft, munitions, space vehicles, as well as ground support vehicles. However, it is impossible to avoid delamination cracks and micro-cracks in fiber-epoxy based composite materials that can even be caused by small impacts during transport and handling of munitions. We have begun developing a self-healing technology, which repairs these defects with high healing efficiency and can be implemented on conventional fiber reinforced – epoxy composites used in munitions and other aerospace applications. In Phase I, we demonstrated that thermally initiated self-healing of an epoxy-based system can be accomplished by controlling its chemistry. The modulus of a self-healed sample was comparable to that of the control sample in the low strain region. Unlike previous approaches, our technology simultaneously closes and seals the crack. In Phase II, the chemistry and microstructure of the self-healing polymeric system will be optimized to achieve the desired mechanical properties and high self-healing efficiency. Additionally, fiber-reinforced composites will be fabricated using this novel polymeric system, and evaluated for performance. The goal is to demonstrate that fiber reinforced composites with high self-healing efficiency can be developed. Two leading research institutions are collaborating with us in the proposed program. In addition, a major defense contractor and supplier to the Air Force is supporting the program.