Flame Retardant Behavior of Polyelectrolyte−Clay Thin Film Assemblies on Cotton Fabric

Abstract

Cotton fabric was treated with flame-retardant coatings composed of branched polyethylenimine (BPEI) and sodium montmorillonite (MMT) clay, prepared via layer-by-layer (LbL) assembly. Four coating recipes were created by exposing fabric to aqueous solutions of BPEI (pH 7 or 10) and MMT (0.2 or 1 wt %). BPEI pH 10 produces the thickest films, while 1 wt % MMT gives the highest clay loading. Each coating recipe was evaluated at 5 and 20 bilayers. Thermogravimetric analysis showed that coated fabrics left as much as 13% char after heating to 500 degrees C, nearly 2 orders of magnitude more than uncoated fabric, with less than 4 wt % coming from the coating itself. These coatings also reduced afterglow time in vertical flame tests. Postburn residues of coated fabrics were examined with SEM and revealed that the weave structure and fiber shape in all coated fabrics were preserved. The BPEI pH 7/1 wt % MMT recipe was most effective. Microcombustion calorimeter testing showed that all coated fabrics reduced the total heat release and heat release capacity of the fabric. Fiber count and strength of uncoated and coated fabric are similar. These results demonstrate that LbL assembly is a relatively simple method for imparting flame-retardant behavior to cotton fabric. This work lays the foundation for using these types of thin film assemblies to make a variety of complex substrates (foam, fabrics, etc.) flame resistant.

Small-molecule-hosting nanocomposite films with multiple bacteria-triggered responses

“…9 Nanoplatelets of smectite family clays such as montmorillonite (MMT), which have a high aspect ratio and a high in-plane elastic modulus, can be included within LbL films at a much higher percentage than their clay-polymer bulk counterparts, resulting in ultrathin LbL assemblies with exceptional mechanical 8 and fire retardant/oxygen barrier properties. 10,11 However, the response properties of nanocomposite LbL constructs, which are central to the biomedical applications of these materials, have remained largely unexplored. We have recently reported on highly swollen, hydrogellike nanocomposite LbL films composed of neutral, temperatureresponsive polymer and MMT nanoplatelets.…”

Deposition Mechanisms in Layer-by-Layer or Step-by-Step Deposition Methods: From Elastic and Impermeable Films to Soft Membranes with Ion Exchange Properties

“…Recently, PEM films incorporating clays or other nanoparticles have been described as excellent fire retardants on the surface of polymer films [75]. More and more PEM films are used as membranes separating the anode and the cathode in fuel cells [76].…”

Surface and Bulk Modification of Synthetic Textiles to Improve Dyeability

“…H. Fu, Ji, Yuan, & Shen, 2005;J. Fu, Ji, Fan, & Shen, 2006), anti-reflection (Hiller, Mendelsohn, & Rubner, 2002), electrical conductivity (Park, Ham, & Grunlan, 2011), anti-flammable (Carosio, Laufer, Alongi, Camino, & Grunlan, 2011;Li et al, 2010;Li, Mannen, Schulz, & Grunlan, 2011), gas barrier Priolo, Gamboa, Holder, & Grunlan, 2010;, and UV resistance (Dawidczyk, Walton, Jang, & Grunlan, 2008). These films, typically < 1µm thick, are created by alternately exposing a substrate to positively-and negatively-charged molecules, polymer electrolytes, or particles, as shown in Figure 12.…”