Flame retardant properties of polyurethane produced by the addition of phosphorous containing polyurethane oligomers (II)

Chemical degradation of used PU was intentionally made by the addition of flame retardants such as tris(2-chloropropyl)phosphate (TCPP), triethyl phosphate (TEP) and trimethyl phosphonate (TMP). Final product obtained after the degradation reaction was named as DEP. The structure of degraded products (DEP) was analyzed by FT-IR and 31P NMR and it turned out to be phosphorous containing oligourethanes. Rigid polyurethane foam was produced using the degraded products (DEP) as flame retardants. The flammability and thermal stability of recycled rigid polyurethane was investigated. The mechanical properties such as compressive strength and tensile strength of recycled polyurethane were also studied. The recycled polyurethane shows reduced flammability and higher thermal stability over virgin polyurethane. Mechanical strength of recycled polyurethane also shows as high as that of virgin polyurethane. In order to evaluate flame retardant properties of the recycled polyurethane foams with various amounts of DEP, heat release rate (HRR) of the foam was measured by cone calorimeter. Scanning electron micrograph of recycled PU shows uniform cell morphology as virgin-PU.