ZnO Microstructures as Flame-Retardant Coatings on Cotton Fabrics

Abstract

In this study, we report a unique strategy that utilizes ZnO and ZnS microparticles and rods as fire-retardant materials when coated onto cotton fabrics. ZnO and ZnO/ZnS microparticles or rods were grown or adsorbed to the surface of cotton fibers. Properties such as heat release rate, total smoke release, and mass loss rate of the materials were tested using a cone calorimeter. ZnO and ZnO/ZnS rods were able to reduce the heat release rate and total smoke release from 118 kW/m 2 and 18.3 m 2 /m 2 to about 70.0 kW/m 2 and 6.00 m 2 /m 2 , respectively. The maximum average rate of heat emission and fire growth rate index, which is used to evaluate the fire spread rate, the size of the fire, and the propensity of fire development, were improved with these coatings and indicate that there are potential applications of these materials as fire retardants.

Zinc Oxide for Functional Textile Coatings: Recent Advances

“…It has been proposed that the flame retardancy of ZnO is based on a condensed phase mechanism of action via the heat barrier effect [141,142]. As a highly thermally stable inorganic material, ZnO can protect the insulation layer on the fiber surface, which reduces the transfer of heat, fuel, and oxygen between the flame and fibers and consequently reduces the rate and intensity of combustion.…”

“…As a highly thermally stable inorganic material, ZnO can protect the insulation layer on the fiber surface, which reduces the transfer of heat, fuel, and oxygen between the flame and fibers and consequently reduces the rate and intensity of combustion. ZnO has already been designated as a smoke suppressant [142].…”

“…There are only a few papers involving ZnO-based flame-retardant textiles. In these studies, ZnO alone or in combination with organic phosphorus compounds was applied to cotton, polyester or cotton/polyester blends [7,84,[142][143][144], but for technical applications, jute and sisal fibers were also used as textile substrates [6,96]. The results showed that the flame retardancy of ZnO-coated cellulose fibers was significantly enhanced if bulk ZnO was replaced with ZnO NPs [6].…”

“…The presence of ZnO increased the limiting oxygen index of the cellulose fibers [6,96], reduced the heat release rate, and acted as a smoke suppressant [144]. Whereas the thermal stability of cellulose fibers was not improved by ZnO, the amount of char residue was significantly increased [13,96,142]. In contrast, the thermal stability of ZnO-treated polyester fibers even decreased compared to untreated fibers [143].…”

Influence of Zinc Oxide Nanoparticles and Char Forming Agent Polymer on Flame Retardancy of Intumescent Flame Retardant Coatings

“…It is eco-friendly and has environmental and industrial catalytic applications. Due to high catalytic properties, ZnO can significantly replace the role of metal catalysts [17][18][19]. Based on catalytic applications of ZnO, we selected it as a synergist, and we expect that it can show positive effects on flame retardancy of IFR systems [20][21][22][23][24].…”