Effect of New P/N Flame Retardant System on Flame Retardancy and Thermal Stability of Thin-walled Polypropylene Materials
In order to solve the difficult problem of flame retardant modification of thin-walled polypropylene(PP),diethyl aluminum hypophosphite(ADP),polyphosphate,and NOR flame retardant(NOR116)were added into PP to prepare flame retardant thin-walled PP.The effects of three flame retardants in different proportions on the flame retardancy,thermal stability and optical properties of PP materials were studied,and the flame retardancy mechanism was explored.The results show that when the mass ratio of ADP∶OL1001∶NOR116 is 5∶5∶1.5 and the total amount of flame retardant is 11.5%,the thin-walled PP(0.5 mm)material can reach VTM-0 grade and LOI is 28.5%,which has good thermal stability and charring performance.The crystallinity of PP decreases after the introduction of flame retardant system.When the total amount of flame retardant is 11.5%,the apparent activation energy of PP increases to 105.5 kJ/mol,which indicates that the introduction of flame retardant system can significantly improve the thermal stability of PP and delay the degradation of materials.NOR116 has obvious synergistic effect in gas phase,and ADP/OL1001/NOR116 system has rapid carbon formation in condensed phase and free radical capture and dilution effect in gas phase.