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Zinc oxide/Zinc sulfide nanostructures as flame retardant coatings

Zinc oxide/Zinc sulfide nanostructures as flame retardant coatings

Yiwei Wang


According to the most recent data available, fires cause approximately 1.3 million accidents annually that result in 3,257 deaths, 15,775 injuries and an estimated $11.6 billion in direct property losses. Flame-retardant materials play an increasingly important role in reducing or preventing damages caused by fires. Organo-halogen compounds, phosphorus compounds, nitrogen-based compounds and nanocomposites are among the different classes of fire retardants developed in the past several decades. In this study, we report that ZnO nanorods and ZnO/ZnS core/shell nanorods show promising behavior as flame-retardant materials when coated onto cotton fabrics. ZnO and ZnO/ZnS nanorods were nucleated and grown onto cotton materials using a multi-step hydrothermal synthesis. TEM and SEM were used to study the morphology of nanorods. The properties of the ZnO and ZnO/ZnS such as heat release rate, total smoke release and mass loss rate of the materials were tested using a cone calorimeter. During the combustion test, ZnO and ZnO/ZnS nanorods were able to reduce the heat release rate and total smoke release from 117.77 kW/m2 and 18.3 m2/m2 to about 70 kW/m2 and 6 m2/m2, respectively. At the end of the test, instead of burning into ash, ZnO and ZnO/ZnS nanorods coated cotton samples were able to maintain the shape and protect the aluminum sample holders from being burned through. The flame-retardant properties were confirmed by the test results.