Researchers from Applied Sciences Inc., a world leader in advanced materials, say carbon nanotubes are ideal materials to pair with nano-sized self-healing capsules in thermoset composites. Applied Sciences is exploring this technology under a NASA Phase I SBIR program targeted at developing self healing composite technology using Pyrograf III carbon nanotubes.
Polymer matrix composites offering multiple advantages of lightweight, high strength and stiffness, vibration damping, and corrosion resistance are becoming widely used in aerospace and commercial applications. A primary weakness of structural composites is damage from impact, where resulting micro-cracks can propagate to allow delamination and/or fiber breakage of the composite, resulting in loss of the excellent physical properties for which composites are selected. Incorporation of carbon nanotubes into the polymer matrix, resulting in a significant increase of the composite interphase, has been shown to mitigate micro-crack formation. Carbon nanotube additives in the matrix have also demonstrated improvement in interlaminar mechanical properties, thermal and electrical conductivity, vibration damping, and fire retardancy. A separate promising tool for addressing damage from impact is the emerging class of self healing materials having the ability to heal micro-cracks and restore mechanical and corrosion resistant properties of the composite. In the awarded effort, a combination of these tools will be investigated to determine the feasibility of incorporating self-healing properties, while concurrently producing multifunctional improvements in interlaminar shear strength, modulus, fracture toughness, transport properties, fire retardancy and vibration damping
Self-healing nano-reinforced composites could be attractive for cryotanks due to carbon nanotubes ability to reinforce the matrix as well as mitigate micro-cracking combined with the capability to repair damage from collisions with debris. In additional, self -healing multi-functional composites could be used for composite fan blades, fan casings or structural components in large-scale structures such as Heavy Lift Vehicle or in-space applications.
Nano-scale self-healing reinforcements could increase the service life and boost physical properties of composites used for aerospace applications and in commercial markets for windmill blades, sporting equipment, automotive, and aerospace structural composites. For example, a reduction in the need to replace windmill blades will result in a lowering of the cost of wind energy and will contribute to the solution of defining economical and renewable energy alternatives for the future.