Abstract: A novel unsatursate cyclophosphazene, hexallyloxy-cyclophosphazene（HACP）was synthesized from hexachlorocyclotriphosphazene（HCCP）and allyl alcohol, with irs structure characterized by FTIR, MS, 1H-NMR, and elemental analysis. The obtained HACP was introduced as a flame retardant into sheet molding compounds of unsaturated polyester, the effect of HACP on the flame retardancy and mechanical properties was researched by limiting oxygen index, scanning electron microscopy, etc. It was found that, with the addition of 15 %HACP, the limiting oxygen index valve of the unsaturated polyester was increased to 36.0%, and the flammability class reached V-0. The carbon residue was increased. The bending strength was 214.63 MPa, and the impact strength was 106.23 kJ/m2.

Key words: unsaturated polyester, cyclophosphazene, flame retardant, synthesis, application