The Use of Ammonium Salts of Oligosulphonic Acids as Flame Retardants for Polymer Compositions

Abstract

The results obtained from a study of both the preparation and application of some oligomeric nitrogen-sulphonic and bromine-nitrogen-containing sulphonic acids as flame retardants in polymer compositions are reported. Flame-retardant poly(chloroprene) compositions with possible applications in cable insulation and conveyor belts, containing an ammonium salt of N-sulphonic acid, antimony trioxide and a chloroparaffin have been obtained. The organic ammonium salt was found to partially replace antimony trioxide, to the extent of 50 to 70 %, in the compositions for conveyor belts. This salt also had a pronounced plasticizing effect, improving the adhesion to the metal cord of the polymer compositions used for making conveyor belts. In addition, heat and smoke release were reduced and the thermal characteristics were improved. Flame-retardant ethylene-propylene copolymer compositions intended for cable insulation were also studied by introducing ammonium salts of bromo – sulphonic and bromo-nitrosulphonic acids and two ammonium salts of N-sulphonic acids. The salts were found to improve the smoke, heat release properties and thermal characteristics, and to exhibit a plasticizing effect. Dynamic thermal analysis showed that the decomposition of the ammonium salts used with antimony trioxide took place in the gaseous phase. The polymer compositions containing ammonium salts of N-sulphonic acids as flame-retardant additives were characterized by improved processability and are environmentally safe.