SUMMARYThe aim of this study was the optimization of cone calorimeter to determine the burning behavior of textile fabrics. In particular, the combustion behavior of commercial polyester textile fabrics with varying densities was studied in terms of time to ignition (TTI), heat release rate (HRR), and relative peak (pkHRR) were monitored. Reproducibility and repeatability of the data have been verified by the influence of instrument variable including incident heat flux, the temperature of ceramic backing pads and retaining grid used during sample mounting as well as sample weight (as the number of fabric layers), the density of textiles, and the relative humidity. A low reproducibility has been obtained when a wire grid was not used to stabilize samples during the tests. The effects of these variables on TTI and pkHRR were observed.

Polyester (PET), cotton (COT), and two relative blend textile fabrics were treated by sol-gel processes. Tetraethoxysilane (TEOS) was used as inorganic precursor of silica phases; furthermore, different TEOS/ H 2 O ratios were examined to explore the effect of the presence of SiO 2 on the thermal and fire stability of the textile fabrics investigated. The distribution and dispersion of SiO 2 were observed by means of scanning electronic microscopy (SEM). SEM magnifications showed the formation of a continuous silica film located in the neighboring fibers; furthermore, in the case of PET, such a film incorporated silica particles with an average diameter ranging between 0.2 and 6 lm. The thermal and thermooxidative stabilities of the treated samples were investigated by thermogravimetric analysis: after the sol-gel treatment, the degradation mechanism was modified both in nitrogen and in air, and the improvement in the thermal stability was attributed to the presence of silica, which played a protective role in the degradation of the textile fabrics. Finally, we investigated the combustion behavior of the textile fabrics by cone calorimetry, measuring the time to ignition, the heat release rate, and the relative peak. The former was found to depend on the type of fabric; the latter generally evidenced a remarkable decrease for all of the treated samples, up to 35% compared to the neat counterparts. This indicated that the sol-gel treatments improved the flame retardancy of the PET/COT fabrics. This conclusion was also confirmed by limiting oxygen index tests, which evidenced burning kinetics changes in the presence of the silica coating.

Abstract:The present paper critically analyzes the potential for commercially available nanoparticles for enhancing the flame-retardant properties of synthetic and natural fabrics and their corresponding blends. Each nanoparticle has been applied to the fabric through a finishing-like process (namely impregnation/exhausting or, more simply, nanoparticle adsorption) in aqueous media and the resulting properties of these fabrics have been assessed in terms of combustion behavior by use of a cone calorimeter under a heat flux of 35 kW/m 2 . The influence of these nanoparticles on the main combustion parameters of polyester, cotton, and some of their blends has been thoroughly discussed. As a result of this discussion, a flame-retardant efficiency ranking of the nanoparticles under review has been established.

SUMMARY Commercial polyester textiles have been finished with hydrotalcite, nanometric titania and silica aqueous suspensions and further characterised in order to investigate their combustion behaviour. Two different features of the finishing procedure have been studied: the role of immersion time and the pH suspension. The corresponding distribution and dispersion of nanoparticles on polyester fibres have been evaluated by scanning electron microscopy coupled to elemental analysis. Furthermore, an eventual surface pre‐treatment of fabrics has been evaluated using cold oxygen plasma. Combustion data have shown that the cone calorimeter is a useful instrumentation to characterise the treated fabrics (when they are washed, as well) in terms of their ability to modify ignition and burning behaviour. Only hydrotalcite‐containing treatments have consistent increases in times to ignite, and hence, flame retardancy levels have been achieved. Copyright © 2011 John Wiley & Sons, Ltd.

Suspensions of nanoparticles (namely, hydrotalcite and nanometric silica) have been employed during the finishing of cotton in order to improve its thermal stability and/or flame retardancy. The immersion approach has also been coupled to a surface pre-treatment of the textile by cold oxygen plasma in order to load a higher amount of nanoparticles onto fibres. The time of immersion and the resulting distribution of the nanoparticles onto the fibres, evaluated by scanning electron microscopy in combination with elemental analysis, have been thoroughly investigated. The present study has shown that the above parameters are functions of nanoparticle type. Pre-treatment by cold plasma has been found to be more effective than the immersion only. As far as the thermal stability and the combustion behaviour of treated cotton are concerned, the nanoparticles turned out to be able to delay the degradation in air, modifying mechanism and kinetics, and at the same time enhancing the flame retardancy of cotton by increasing the time to ignition and decreasing the heat release rate peak during the combustion. The joint effect of the two nanoparticles has also been evaluated and found more efficient than the effect of single species.

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