Other Smoke Suppressants

In addition to the most common molybdenum compounds, iron compounds, and transition metal compounds that can be used as smoke suppressants, other compounds have also been explored in the smoke suppression research of flame retardant materials. Alfa Chemistry offers a range of compounds with smoke suppression potential to address smoke and toxicity issues during polymer combustion. If the smoke suppressant you are interested in is not found in the product list, please contact us to discuss your specific needs.

Classification And Smoke Suppression Mechanism

• Mg-Zinc Compounds

The flame-retardant and smoke-suppressing effect of magnesium-zinc compounds in semi-rigid PVC is mainly through catalytic solid-phase decomposition in the solid phase, which promotes the formation and reorganization of the carbon layer, thereby reducing the generation of benzene and volatile hydrocarbons. The formation of dense and low brittle carbon layers and the reduction of total organic volatile compounds may explain the flame retardant properties of this additive. The significant reduction in the amount of benzene released is the main reason for the high smoke suppression efficiency of the additive.

• Metal Oxides

Some metal (Ba, Sr, Ca) oxides can also remove smoke. Because they can catalyze hydrogen molecules and split water molecules to produce H·. H· can further react with water to form OH·, which can convert soot to CO through oxidation. [1]



• ZS And ZHS

Zinc stannate (ZS) and zinc hydroxystannate (ZHS) are effective flame retardants and smoke suppressants for many synthetic polymers because of their synergistic reaction with halogenated and halogen-containing polymers. ZHS and ZS reduce the production of smoke, CO₂ and CO from combustion. Furthermore, they are less toxic, safe and effective at low doses. Besides, they are less toxic, safe and effective at low doses.

There are two possible mechanisms:

(1) Accumulation of carbon deposits in the condensed phase through the cross-linking reaction, resulting in the reduction of flammable and volatile products.

(2) Form volatile tin compounds, as a gas-phase catalyst, to promote the conversion of CO and soot combustion zone.

• Metal Salts

8-Hydroxyquinoline heavy metal (Fe, Mn, Cr) salts, copper salts, lead salts and phthalocyanine free radical initiators (such as tetraphernl-lead) can react with aromatic compounds in the gas phase, so they can be used as smoke suppressants for styrene plastics.

Research Information

Smoke suppression of graphene oxide

Weizhao Hu et al. developed a well-defined functionalized graphene oxide (FGO) grafted by a hyperbranched flame retardant and used it to reduce the flammability and toxicity of polystyrene (PS). In this work, the uniform dispersion of the introduced FGO in the PS matrix enhances the barrier effect, thereby reducing the peak heat release rate, total heat release, and toxic gases released during combustion. These toxic volatiles include aromatic compounds, carbonyl compounds, and carbon monoxide. [2]

The preparation route of PS-FGO nanocomposites [2]

References

1. Jianjun Li, et al. (2019). "7. The mechanism of smoke suppression". Theory of Flame Retardation of Polymeric Materials, pp. 195-210.
2. Weizhao Hu, et al. (2015). "Hyper-branched polymer grafting graphene oxide as an effective flame retardant and smoke suppressant for polystyrene," Journal of Hazardous Materials 300, 58-66.