Adhesives for Bonding Large High-Temperature Sandwich Structures 670858
Manufacturing technology development programs for high-temperature-resistant polybenzimidazole and polyimide laminating and adhesives systems and core materials, developed under Air Force sponsorship, have been initiated to fulfill aerospace thermal and structural plastics application requirements. The general objectives are to investigate and evaluate materials and processing variables as they apply to the fabrication of large sandwich structures which incorporate polybenzimidazole prepreg, high-temperature adhesives, and high-temperature honeycomb cores; to develop manufacturing methods for fabricating large plastic sandwich structures which incorporate high-temperature adhesive and honeycomb core, and polybenzimidazole prepreg; and to fabricate three large sandwich structures, using selected materials and processing conditions.
Candidate high-temperature-resistant adhesive systems evaluated included: FM-34, PI 5505, Metlbond 840, and Imidite 850.
Room temperature and 650 F sandwich flexural shear and flatwise tension test results of generally equal magnitude were witnessed for all adhesives; however, the less complex processing and lower cure and postcure temperature requirements of the polyimide system resulted in the selection of polyimide FM-34 adhesive for the first NRD-66-1000 sandwich radome specimen.