Molybdenum compounds as flame‐retardants and smoke‐suppressants in halogenated polymers

Abstract

The hazards resulting from smoke emission were widely recognized in the early 1970s as a result of several major fire disasters. Since that time considerable interest has been shown in the development of smoke-suppressants. This paper reviews some of the very promising results that have been obtained using molybdenum compounds as flame-retardants and smoke-suppressants in halogenated polymers. They have been shown to be effective in both rigid and flexible grades of PVC. In the rigid grades these compounds can reduce smoke emission by a t least 80%. Reductions in excess of 50% have been observed with typical plasticized formulations, although the magnitude of the effect here depends on both the type and level of plasticizer. Comparisons of the results of different smoke tests suggest that the small-scale tests commonly used do not fully reflect the true extent of the smoke-reductions that are obtainable with these compounds. Significant reductions in smoke-emission have also been obtained with halogenated polyester thermosets and chlorinated elastomer formulations. With the polyesters some of the best results occurred when molybdenum oxide was used in conjunction with aluminium trihydrate. In all cases these compounds proved to have significant flame-retardant properties. Reference has been made in the paper to their mode of activity but the actual mechanistic investigations have not been discussed in detail.Many compounds have been suggested in the literature for use as smoke-sutmressants.2 Thev can be classified as 0308 0501 ,'86/02oO63-07$05.OO 1186 by

Flame-retardant and smoke-suppressant properties of zinc borate and aluminum trihydrate-filled rigid PVC

“…Smoke suppression during combustion of PVC is getting more and more attention. Additives used to reduce the flammability and smoke formation of PVC have been studied and reported 1–13. The additives include compounds containing antimony, tin, zinc, copper, iron, and molybdenum, etc., while the most important commercial smoke suppressants are zinc and molybdenum compounds.…”

Flame-retardancy and Smoke-suppression Studies on Ferrocene Derivatives in PVC

“…The most effective smoke-suppressant additives for PVC are generally compounds of the transition metals, including molybdenum and copperl5> 17) 18, 2o tin16 and zinc.9 These compounds are believed to modify the degradation mechanism occurring during pyrolysis or ~-Author to whom correspondence should be addressed. burning, by cross-linking to increase char formation.…”

Flame retardancy in fabric consisting of cellulosic fiber and modacrylic fiber containing fine‐grained MoO3 particles

“…The results of flammability measured by the vertical flame spread test are shown in Table I. Although all oxides and a hydroxide examined in the present study are known as flame retardant or smoke suppressing agent for halogen containing polymers in the present studies [2][3][4][5][6][7][11][12][13][14][15][16], only MoO 3 promotes excellent flame retardancy when it is fine-grained. On the other hand, no improvements in the flame retardancy are observed for other metal compounds by reduction of the particle size.…”