Effect of Phosphorus-Containing Fire-Retardant Systems on Fireproofing and Processing Indexes of Polypropylene

The thermal stability of polypropylene composites containing the microencapsulated ammonium salt of methylphosphonic acid amide and copper-zinc-boron compounds as a fire retardant was investigated. It was shown that incorporation of dizinc hexaborate increases the thermal stability period (MFI of 15 min) in comparison to this index for the composite containing a fire retardant alone (MFI of 2 min), which is due to slowing of decomposition of the fire retardant. It was found that dizinc hexaborate alters thermooxidative degradation of polypropylene containing microencapsulated methylphosphonic acid amide ammonium salt by decreasing the temperature and maximum rate of decomposition. The number of gaseous compounds liberated in thermooxidative decomposition of the composite is much lower than for the initial polypropylene.