Study Of Synergism Of Metal Oxide On Intumescent Flame Retardant Polypropylene System

Polypropylene (PP) is one of the five general plastics with heat resistance, light weight, easy processing, good chemical resistance and has a broad prospect of application in life and production. However, PP is easy burning with releasing a lot of heat and smoke. The large area fire is easy caused for its fast flame propagation speed and draining phenomenon. It will release a lot of smoke which cause choking sexual atmosphere in combustion process. Its application field is restricted for people’s life safety. Therefore, PP need be modified on flame retardant in order to improve the fire safety.Firstly, melamine salt of pentaerythritol phosphate (PPM) was synthesized from phosphoric acid, pentaerythritol and melamine in this paper. Its structure was characterized by FTIR. The influence factors on intumescent degree, residual carbon rate and yield such as composition of components, reaction temperature, the reaction time and solvent were investigated. Thermal stability of PPM was investigated by TG Then PP/PPM> PE/PPM intumescent flame retardant systems were prepared. Flame retardant properties, mechanical properties, thermal stability performance of PPM’s quantity added on PP/PPM^ PE/PPM systems were investigated. In the end, Sb2O3、La2O3、 ZrO2、 MnO2、CeO2 were selected as synergistic additive. Flame retardant properties, mechanical properties, thermal stability performance of metal oxide added in PP/PPM^ PE/PPM systems were investigated.The results showed that the oxygen index of PP/PPM, PE/PPM system increased with the adding amount of PPM and mechanics performance declined. PP/PPM system could forming a dense thick cover carbon layer when 20phr PPM was added in it in the combustion process and it still had 5.52wt% residues in 600℃.When PPM’s adding quantity was 20phr, mechanics performance of metal oxide/PP/PPM intumescent flame retardant system declined with the increase of adding amount of metal oxide. When the adding amount of Metal oxide was less than 3phr, the oxygen index of the system was improved in different degree. When the adding amount of Metal oxide was 2phr, carbon layer’s internal morphology had not changed very much, but external morphology varied with the kind of metal oxide added. The intumescent flame retardant system which CeO2 added had best external morphology of residual carbon layer, so the carbon layer could play a very good coverage.When a moderate amount of metal oxide such as CeO2 that generally less than 2phr is added in intumescent flame retardant system as flame retardant synergist, the flame retardant performance is improved greatly.