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A flame-retardant poly(acrylic acid) (FR-PAA) was prepared by copolymerization of N-(2-(5,5-dimethyl-1,3,2-dioxaphosphinyl-2-ylamino)-ethylacetamide-2-propenyl acid (DPEPA) and acrylic acid and used to fabricate various FR-PAA/montmorillonite (MMT) thin films via layer-by-layer (LbL) deposition as a flame-retardant coating system for cotton fabric. Thermogravimetric analysis (TGA) indicated that treatment of FR-PAA/MMT thin films improved the thermal stability of cotton fabric. Cone calorimeter testing showed that the cotton fabrics coated with the FR-PAA/MMT thin films had less flammability with lower peak heat release rate (PHRR), lower total heat release (THR), and lower average mass loss rate (AMLR). In addition, scanning electronic microscopy (SEM) demonstrated that the surface of the fabrics coated with FR-PAA/MMT films after combustion was covered by a layer of continuous and compact char.

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Multi-walled carbon nanotubes (MWNTs) were used as sorbent for flow injection (FI) on-line microcolumn preconcentration coupled with flame atomic absorption spectrometry (FAAS) for determination of trace cadmium and copper in environmental and biological samples. Effective preconcentration of trace cadmium and copper was achieved in a pH range of 4.5 -6.5 and 5.0 -7.5, respectively. The retained cadmium and copper were efficiently eluted with 0.5 mol L 21 HCl for online FAAS determination. The MWNTs packed microcolumn exhibited fairly fast kinetics for the adsorption of cadmium and copper, permitting the use of high sample flow rates up to at least 7.8 mL min 21 for the FI on-line microcolumn preconcentration system without loss of the retention efficiency. With a preconcentration time of 60 sec at a sample loading flow rate of 4.3 mL min 21 , the enhancement factor was 24 for cadmium and 25 for copper at a sample throughput of 45 h 21 . The detection limits (3s) were 0.30 and 0.11 mg L 21 for Cd and Cu, respectively. The precision (RSD) for 11 replicate measurements was 2.1% at the 10-mg L 21 Cd level and 2.4% at the 10-mg L 21 Cu level. The developed method was successfully applied to the determination of trace Cd and Cu in a variety of environmental and biological samples.

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