Development of LaRC (TM): IA thermoplastic polyimide coated aerospace wiring

NASA Langley has invented LaRC(exp TM) IA and IAX which are thermoplastic polyimides with good melting, thermal and chemical resistance properties. It was the objective of this contract to prepare and extrude LaRC (exp TM) polyimide onto aircraft wire and evaluate the polymers performance in this critical application. Based on rheology and chemical resistance studies at Imitec, LaRC (exp TM) IAX melts readily in an extruder, facilitating the manufacture of thin wall coatings. The polyimide does not corode the extruder, develop gel particles nor advance in viscosity. The insulated wire was tested according to MiL-W-22759E test specifications. The resulting wire coated with LaRC (exp TM) IAX displayed exceptional properties: surface resistance, non blocking, non burning, hot fluid resistance, impulse dielectric, insulation resistance, low temperature flexibility, thermal aging, wire weight, dimensions, negligible high temperature shrinkage and stripability. The light weight and other properties merit its application in satellites, missiles and aircraft applications. The extruded IAX results in a polyimide aircraft insulation without seams, outstanding moisture resistance, continuous lengths and abrasion resistance.