Processing Characteristics of TEEK Polyimide Foam

Abstract

High performance polymeric foams have experienced a growing demand in aerospace applications such as cryogenic insulation, flame-retardant panels and structural sub-components. The Next Generation Launch Technology (NGLT) program requires foams capable of retaining their structural integrity while providing insulating capabilities in a liquid hydrogen environment. NASA Langley Research Center (LaRC) and Unitika Ltd co-developed a polyimide foam processed from a fine powder of salt-like foaming precursor isolated from solution via solvent evaporation. This paper reports the foaming characteristics of this precursor based on rheometric, calorimetric, thermogravimetric and chromatographic characterization methods. The degree of foaming varied significantly as a function of process heating rate and hold temperatures. Results from the battery of measuring techniques employed afford a complete picture of the foaming and curing mechanism for the subject polyimide foam.