Polyimide Resins Resist Extreme Temperatures
- Sunday, 01 November 2009
Originating Technology/NASA Contribution
Spacecraft and aerospace engines share a common threat: high temperature. The temperatures experienced during atmospheric reentry can reach over 2,000 °F, and the temperatures in rocket engines can reach well over 5,000 °F.
To combat the high temperatures in aerospace applications, Dr. Ruth Pater of Langley Research Center developed RP-46, a polyimide resin capable of withstanding the most brutal temperatures. The composite material can push the service temperature to the limits of organic materials.
Designed as an environmentally friendly alternative to other high-temperature resins, the RP-46 polyimide resin system was awarded a 1992 “R&D 100” award, named a “2001 NASA Technology of the Year,” and later, due to its success as a spinoff technology, “2004 NASA Commercial Invention of the Year.” The technology’s commercial success also led to its winning the Langley’s “Paul F. Holloway Technology Transfer Award” as well as “Richard T. Whitcom Aerospace Technology Transfer Award” both for 2004. RP-46 is relatively inexpensive and it can be readily processed for use as an adhesive, composite, resin molding, coating, foam, or film. Its composite materials can be used in temperatures ranging from minus 150 °F to 2,300 °F. No other organic materials are known to be capable of such wide range and extreme high-temperature applications.
In addition to answering the call for environmentally conscious high-temperature materials, RP-46 provides a slew of additional advantages: It is extremely lightweight (less than half the weight of aluminum), chemical and moisture resistant, strong, and flexible.
Pater also developed a similar technology, RP-50, using many of the same methods she used with RP-46, and very similar in composition to RP-46 in terms of its thermal capacity and chemical construction, but it has different applications, as this material is a coating as opposed to a buildable composite.
A NASA license for use of this material outside of the Space Agency as well as additional government-funded testing proved that RP-46 is even more exceptional than originally thought.
Unitech LLC, of Hampton, Virginia, is an advanced materials solutions provider specializing in advanced materials technology, engineering, manufacturing, research and development, and prototyping services. In 2001, Unitech received a nonexclusive license from NASA for commercialization of the cost-effective, weight- and space-saving high-temperature material RP-46 and the RP-50 coating.
Using the NASA-developed technology, Unitech applied for a Small Business Innovation Research (SBIR) contract with the U.S. Navy to develop insulation for an all-electric ship that was under consideration. One of the considerations the Navy had was the need for an extremely fire-resistant material. While initial NASA testing had proven that RP-46 could withstand temperatures in the range of 700 °F, the Navy was looking for a material that could withstand anywhere from 8,000 to 250,000 volts of electricity. Under this Navy SBIR, independent testing showed that RP-46 could withstand temperatures up to 2,300 °F. This discovery made it ideal for use in the original Navy application, but also opened up the possibility that the material could be used in future applications, like in high-voltage insulation for high-rise buildings, where great amounts of power run long distances.