The effect of various nanomaterials on the thermal degradation of polymers
Nanocomposites of ethylene-vinyl acetate copolymer (EVA), polyethylene (PE), polystyrene (PS) and poly(methyl methacrylate) (PMMA) were prepared with a series of nanomatenals as carbon nanotubes, organically-modified layered double hydroxides and montmorillonite by melt blending, and in the case of PMMA by bulk polymerization. The dispersion of the inorganic nanomatenals was evaluated by X-ray diffraction and transmission electron microscopy, which confirmed nanocomposite formation. The thermal stability of nanomatenals and nanocomposites was assessed by thermogravimetnc analysis and the identity of the degradation products was investigating by in situ Fourier transform infrared spectroscopy, gas chromatography-mass spectroscopy, nuclear magnetic resonance and ultraviolet spectroscopy. The flammability properties of all the nanocomposites were evaluated using the cone calorimeter. The changes in the degradation products of PE, EVA, PS and PMMA nanocomposites were followed and the relationship between these changes and the unique structure of montmonllonite was highlighted. Modified clays known to have high thermal stability (quinolinium and oligomeric clays) have been shown to be suitable for nanocomposite synthesis with poly(ethylene terephtalate) (PET). Also, other thermally stable surfactants were synthesized and used for clay modification. The nanocomposites of these organo-clays with PS, acrylonitrile-butadiene-styrene copolymer (ABS) and high impact polystyrene (HIPS) were prepared and compared with imidazolium clays. A variety of additives have been evaluated as potential fire retardants for polyureas with cone calorimetry being the method of evaluation. The additives that have been evaluated include minerals (alumina trihydrate), bromine-, nitrogen- and phosphorus-based fire retardants. The major criteria for evaluation were the reductions in the peak heat release rate and the total heat release, the evolution of smoke and dripping.
Marius Cristian Costache,
"The effect of various nanomaterials on the thermal degradation of polymers"
(January 1, 2006).
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