N-P HALOGEN FREE FLAME RETARDANT AND FLAME RETARDANT GLASS FIBER REINFORCED NYLON 6

Nitrogen-phosphorus flame retardant(MPP) was prepared through thermal polymerization of melamine phosphate(MP) at a certain temperature.The obtained reaction product was then used to flame-retard the glass fiber(GF) reinforced nylon 6(PA6).The problem of candlewick effect' related to the glass fiber was successfully solved by introduction of the char forming catalyst heteropolyacid(HPA) and the flame retardant modifier(CR) into the flame retarding system.Particularly,the effect of HPA and CR on the flame retardancy of the reinforced PA6 was systematically investigated.The experimental results show that the prepared flame retardant(MPP) is composed of melamine polyphosphate,which proves to be the main component,and melamine pyrophosphate.It is also found that HPA and modifier CR have a synergistic effect on MPP in flame-retardant glass fiber reinforced PA6.The synergistic mechanism was explained by the accelerated char forming reaction caused by the introduction of HPA and modifier CR and hence the improved structure of charred layer during combustion of material.Upon addition of 2% HPA and 2% modifier CR to the flame retarding system,the flame retarded GF reinforced PA6 can achieve UL 94 V-0 level at(1.6) mm thickness,and possesses good mechanical properties with tensile strengt3 of 81MPa and Young′s modulus of 9767 MPa.