NASA Uses Polyimide to Study Insulation of Electric Engines in Aerospace

A thermoplastics polyimide (PI) has been tested by NASA’s Glenn Research Center in Cleveland, Ohio, that demonstrates interesting properties, making it a candidate for the electrical wiring requirements for future aerospace transportation technologies. Called Aurum, the material is a semicrystalline PI suitable for powder coating, injection molding and extrusion coating, with the highest glass transition temperature in its class. The extrusion processing of Aurum for wire insulation is said to be highly economical, enabling extremely thin layers and offering high elasticity as well as good compatibility with cooling and lubricating oils.

Produced by Mitsui Chemicals, Aurum PI is sold by BARplast in the U.S., which supplied the material to NASA, and Bieglo in Europe. It boasts one of the highest glass transition temperature (Tg) of 473°F (245°C) of any commercially available thermoplastics. (BARplast is a subsidiary of Germany-based Bieglo Group, a distributor of high -performance plastics serving a wide range of industries, including aerospace, automotive and electrical.)

In a NASA white paper presented at the May 2024 SAMPE conference, researchers pointed out there are “electrical wiring requirements for next-generation air and space transportation engineering designs, with continuous operation temperature requirements of up to 392°F (200°C).” The objective of the study was to assess the potential of thermoplastic polyimides as a high-temperature electrical insulation solution. Furthermore, the white paper highlighted the need for “thermoplastic electrical insulation materials systems to improve thermal management in high power density electric motors.” It also stated that “a melt processable PI with high service temperatures is of interest as an electrical insulation candidate material.” Additionally, melt processing enables facile dispersion of fillers within a polymer matrix which can impart additional functionality such as thermal conductivity, according to the researchers.