An XPS investigation of thermal degradation and charring on poly(vinyl chloride)-clay nanocomposites

More information concerning the thermal degradation and charring of nanocomposites of poly(vinyl chloride), dioctyl phthalate and clay has been obtained by the use of X-ray photoelectron spectroscopy and the acquisition of the carbon (Cls), chlorine (Cl2p), and oxygen (O1s) spectra. In the cases of polystyrene-clay and poly(methyl methacrylate)-clay nanocomposites, it has been shown that the clay migrates to the surface as the temperature is raised and the polymer degrades, thereby confirming the barrier properties as a mechanism by which these materials function. For PVC-clay nanocomposites the surface at high temperatures is dominated by carbon, and not the oxygen of the clay. The presence of the clay does retard the chain-stripping degradation of the PVC and the enhanced char formation accounts for the observation of enrichment of carbon. (C) 2002 Elsevier Science Ltd. All rights reserved.