The incorporation of a polyCferrocene-1, 2 (1, 3 1, 1')diylmethylenel fraction with = 2100 as a smoke suppressant additive into both unplasticized and di(2-ethy1hexyl)phthalate-plasticized, calcium carbonate-filled poly( vinyl chloride) (PVC) compositions entails appreciable reductions in smoke evolution during combustion tests relative to unmodified formulations. Best results, with smoke density reductions in the range 25-80%, are obtained at the 3% loading level, with higher additive concentrations causing no further improvements. The findings of this study may have implications on the design of other polymeric engineering materials exposed to potential fire hazards.Keywords: Polyferrocene, smoke suppressant, poly(viny1 chloride), PVC, smoke density, maximal optical density material and evaporate from the surface 2 e 9 3 on long-term storage or under conditions of slow build-up of a high-temperature environment as realized in certain fire situations, which may lead to additive depletion in the most critical phase of pyrolytic degradation and combustion.As part of a comprehensive program to develop ferrocene-containing smoke suppressants possessing structures incapable of migration and volatilization in hot environments, the present study is concerned with the incorporation of a polymeric ferrocene compound 1 into PVC compositions and an evaluation of its smokesuppressing properties.I& J. 1