Poly(vinyl chloride) composition. II. Study of the flammability and smoke‐evolution of unplasticized poly(vinyl chloride) and fire‐retardant additives

Abstract The influence of natural, activated, and modified microzeolite with the general formula Me 2/ m · Al 2 O 3 · n SiO 2 · p H 2 O (where Me = Fe 3+ , Ca 2+ , Mg 2+ , Zn 2+ , K + , Na + ) and an organic additive, such as ammonium sulfamate combined with ammonium sulfate on smoke formation and flammability of suspension poly(vinyl chloride) has been studied in the present work. Microzeolite in native (i.e., natural), activated, and modified forms has been found to possess both fire‐retardant and smoke‐suppressant effects in solid poly(vinyl chloride) compositions. Such effects have been best revealed by modified microzeolite containing 3,5–4% zinc. On the other hand, the ammonium sulfamate combined with ammonium sulfate is believed to act as a strong smoke‐suppressant additive. Thermogravimetric examinations and limited oxygen index measurements show that microzeolite acts as a fireresistant and smoke‐suppressant additive predominantly in the condensed phase. The ammonium sulfamate in combination with ammonium sulfate gives evidence of the same effects, mostly in the gaseous phase.