The lowering of ignitability and flammability of polyethylene (PE) and the production of fire-retarding materials has become an urgent problem because of the demand of fire safety. In our article, a new charring agent (CA), a derivative of triazines, was synthesized by charging 2-amino-4,6-dichloro-s-triazines and diethylenetriamine into a reactor to conduct the solution polycondensation reaction, and the synthetic conditions of monomer and CA, such as temperature, time, etc., were investigated. Both the monomer and the resulting polymer were characterized by mass spectrum (MS), Fourier transform infrared (FTIR) spectroscopy, H-1-NMR, and elemental analysis. The intrinsic viscosities and flame-retardancy property of CA were also studied. It was found that the incorporation of ammonium polyphosphate (APP) and CA into low-density polyethylene (LDPE) has a distinct effect on thermal and flame-retardancy behavior. (C) 2004 Wiley Periodicals, Inc.