Syntheses and Properties of Halogen Reactive Flame Retardants and Flame Retarded Unsaturated Polyester Resins

Five flame retardants: 2, 2-bis3, 5-dibromo-4-(2-hydroxy-ethoxy)-phenyl propane, 2, 2-bis3, 5-dichloro-4-(2-hydroxy-ethoxy)-phenylpropane, 2, 2-bis-(3, 5-dibromo-4-(carboxy-methoxy)-phenylpropane, 2, 2-bis(3, 5-dichloro-4-(carboxy-methoxy)-phenylpropane, bis3, 5-dibromo-4-(2-hydroxy-ethoxy)-phenylsulfon were prepared from halogenated bisphenol A or bisphenol S. Using these compounds, ten unsaturated polyester resins were synthesized. These resins were evaluated for thermal mechanical characteristics, oxygen index and thermal analysis, such as TGA and DTA. From these we conclude that the derivatives of bromobisphenol A are better than the derivatives of chlorobisphenol A as flame retardants. Fire resistance is not improved when a compound which contains not only bromine but also sulfur is used as flame retardant. 2, 2-bis3, 5-dihalo-4-(carboxy-methoxy)-phenylpropane is much better than 2, 2-bis3, 5-dihalo-4-(2-hydroxy-ethoxy)-phenylpropane as a reactive flame retardant in unsaturated polyester resins.