NASA Langley researchers have developed a multi-layered self-healing material system for impact mitigation from ballistic or hypervelocity events, for example, micrometeoroids or orbital debris. The system is constructed by sandwiching a reactive liquid monomer formulation between two solid polymer panels.
Besides space exploration, the material suits many other applications such as fuel tanks and hydraulic insulation. It is capable of self-healing capability over a wide range of temperatures and self-healing from high-velocity events is rapid. Also, the material can be tailored for use in structural load-bearing applications. Typical applications include aircraft and aerospace, MMOD protective liners in space habitats/structures, radiation shielding, encasing for fuel lines and tanks, encasing for hydraulics, wire insulation material, and any pressure loaded type structures.
The material employs a tri-layered structure, comprised of solid plastic front and back layers sandwiching a viscous, reactive liquid middle layer. Combined, this system provides rapid self-healing following high velocity ballistic penetrations. Self-healing in the front and back layers occurs when the puncture event creates a melt state in the polymer materials and the materials melt elasticity snaps back and closes the hole.
The viscous middle layer augments the self-healing properties of the other layers by flowing into the gap created by a ballistic puncture and concurrently solidifying due to the presence of oxygen. Thus, this innovation has two tiers of self-healing: a puncture-healing mechanism triggered by the projectile and a second mechanism triggered by the presence of oxygen. For more details, peruse the Multi-layered Self-healing Material System datasheet.
Langley Research Center
Mail Stop 151
Hampton, VA 23681