Use of the TMA film tension technique for differentiating polymeric materials in the Space Shuttle program

Abstract

During the recent processing of a forward segment of the Reusable Solid Rocket Motor (RSRM) for the Space Shuttle, the topcoat white paint turned light brown after autoclave cure of the case insulation. Thermomechanical analysis (TMA) in the film tension mode produced modulusvs. temperature data that helped to explain why a certain insulation vacuum bagging material contributed to the brown paint color. TMA film tension data was also obtained on lab-created white and brown topcoat paint samples (with and without primer). The brown/white ratios of moduli were about 2/1 and 4/1 for topcoat/primer and topcoat only samples, respectively, from 25 to 55‡C.