A new intumescent flame retardant(IFR) system,which was composed of a flame retardanted oligomer(PSPTR) and phenol formaldehyde resin(PF),was used to impart flame retardancy for ABS resin.The flammability properties of PSPTR-PF/ABS composites were investigated by limiting oxygen index(LOI) and vertical burning test(UL-94),respectively.The results show that the LOI value of PSPTR-PF/ABS composites reach 28.2,and UL-94 reached V-1 rating when the total addition mass fraction is 30%,in which the mass ratio of ...