Abstract: An intumescent flame retardant (IFR) containing dibromoneopentyl glycol (DBNPG), pentaerythritol (PER), and microencapsulated ammonium polyphosphate (APP) was introduced into linear low density polyethylene (PE-LLD). Experimental results proved that an appropriate content of DBNPG improved the compatibility of PE-LLD and IFR, enhanced the tensile properties and the melting viscosity, promoted the formation of a closed char layer. However, excessive DBNPG content lowered the soften temperature of IFR, decreased the melt viscosity, and thus destroyed the closeness of the char layer, deteriorated the thermal barrier property, weakened the flame retardancy. When the ratio of PER/DBNPG was 70.0/115.5, and the ratio of PELLD/IFR was 70/30, the composite exhibited the optimal flame resistance.

Key words: dibromoneopentyl glycol, flame retardancy, linear low density polyethylene, compatibility, melting viscosity