CONTROLLED CHEMICAL MODIFICATION OF ARAMID FIBER SURFACES TO ENHANCE FLAME RETARDATION

CHEMICAL TREATMENT OF EXISTING ARAMID FIBERS IS PROPOSED TO INCREASE FLAME RETARDATION BY ENHANCING CHAR FORMATION AT THE SURFACE. SUCH SURFACE-CONTROLLED CHEMICAL MODIFICATION WITHOUT COMPROMISING THE FIBER'S MECHANICAL PROPERTIES, HAS BEEN DEMONSTRATED IN STUDIES UNRELATED TO IMPROVE FLAMMABILITY BEHAVIOR. THIS APPROACH IS SUBSTANTIVELY DIFFERENT FROM OTHER CURRENT APPROACHES TO IMPROVE FLAME RETARDANCE INCLUDING COATING WITH ALUMINUM AND BLENDING OF ARAMID POLYMERS OF DIFFERENT MACRO-STRUCTURE. THE FLAME RESISTANCE SHOULD DEVELOP FROM BOTH QUENCHING BY BROMINE RELEASE AND THERMALLY INDUCED INTERNAL CYCLIZATION AND INTER-MOLECULAR POLYMER CROSSLINKING AT THE SURFACE OF THE FIBER. MECHANICAL PROPERTIES OF THE TREATED FIBERS WILL BE EVALUATED IN COMPARISON WITH UNTREATED CONTROLS. FLAMMABILITY CHARACTERISTICS INCLUDING FLASH POINT, SELF EXTINGUISHING BEHAVIOR AND GASES GENERATED UPON PYROLYSIS WILL BE DETERMINED FOR THOSE FIBERS COMPARABLE IN MECHANICAL PROPERTIES TO UNTREATED FIBERS. OPTIMIZATION OF TREATMENT CONDITIONS AND PRACTICALITY OF COMMERCIALIZATION CAN BE DETERMINED IN A PHASE II EFFORT.