The water resistance of surface-modified APP with melamine-TDI in LLDPE

Ammonium polyphosphate (APP) which was surface-modified with melamine (MA) and 2,4-toluene diisocyanate(TDI) in turn was used as flame-retardant in linear low density polyethylene (LLDPE). Its water resistance in LLDPE was respectively evaluated with its water-solubility, the limited oxygen index(LOI)changes and P content changes of the LLDPE which being immersed in water 180 h at room temperature. Its compatibility with LLDPE was observed with scanning electron microscope (SEM). As a result, the water-solubility of the surface-modified APP reduced. When the LLDPE was treated with surface-modified APP, its LOI and P content changes were less than that treated with unmodified-APP after being immersed in water. The surface-modified APP was better compatible with LLDPE than unmodified APP.