A NEW THERMOPLASTIC FLUOROPOLYMERCOMPOSITE MATERIAL FOR NONFLAMMABLETANKS AND STRUCTURES

摘要

XCOR Aerospace has developed a non-flammable, high-strength, lightweight compositernmaterial, trademarked as Nonburnite, which is suitable for making liquid oxygen (LOX) tanksrnfor space flight service. We expect the new composite material's superior performance willrnresolve existing problems with cryogenic and liquid oxygen storage/tank materials. We beganrndevelopment of this composite because XCOR’s vehicles, as well as most of our customers'rnvehicles, require lightweight, long-service life LOX tanks. This material has numerousrnadvantages over other, more traditional composites. It is naturally resistant to microcracking, hasrna low coefficient of thermal expansion (CTE), and has inherent resistance to combustion. Whenrnused in a skin-foam-skin composite, it also serves as thermal insulation as well as structure.rnAdditionally, it is durable, repairable, and can withstand extreme hot and cold temperatures. Thernfluoropolymer composite maintains strength and flexibility at extreme temperatures (-260 to plusrn280 degrees C/-436 to plus 536 degrees F). We recently finished the first round of qualificationrntests using Dupont’s newly released Teflon~? PFA TE-7224 dispersion formula, which replacesrn335. In a previous NASA contract XCOR conducted various tests on skin and sandwich coupons,rnas well as cylinders made with 335. This paper details this prior work along with our latestrnfabrication and test experience with TE-7224.