High Temperature Polymeric Wire Insulation

The need for high temperature resistant polymeric wire insulation is recognized by the military/aerospace community and industrial companies. Dual use applications are here today for new polymeric coated or wrapped film wire insulation materials suitable for continuous or intermittent performance at ≥300°C. The new materials are necessary to replace state-of-the-art polyimide polymers such as Kapton^R and fluorocarbon resins such as Teflon^R and its derivatives. These existing and qualified insulation materials are generally limited to ≤250°C service and are not capable of meeting existing or emerging needs for higher temperature capable polymers suitable for highly demanding power generation and distribution applications.

TRW conducted an investigation under USAF sponsorship beginning in 1988 and concluding in 1991 on Contract F33615-88-C-2909 to identify and evaluate polymeric wire insulation candidates suitable for ≥300°C service. Five advanced polymeric materials were studied in this work employing Kapton as the control insulation material. The results of this work clearly demonstrated that two polymeric materials, Partially Fluorinated Polyimide (PFPI) and Upilex^R S polyimide were vastly superior to Kapton in thermal-oxidative stability and retention of superior electrical properties at 300°C. Significant performance improvement of PFPI and Upilex S over Kapton were also determined for moisture, ultraviolet light and basic media exposure resistance.