Two blends of acrylonitrile-butadiene-styrene with unplasticised poly
(vinyl chloride) and a tertiary blend of acrylonitrile-butadiene-styre
ne, unplasticised poly (vinyl chloride) and poly (propylene) containin
g a smoke suppressing iron compound gives good reductions in smoke and
high yields of carbonaceous char when heated in air. Relationships be
tween char formation and smoke production are discussed.