The thermal degradation of poly(methyl methacrylate) nanocomposites with montmorillonite, layered double hydroxides and carbon nanotubes

The thermal degradation of poly(methyl methacrylate) and its nanocomposite has been studied to determine if the presence of clays (anionic and cationic) or carbon nanotubes has an effect on the degradation pathway. Nanocomposite formation has been established by X-ray diffraction and transmission electron microscopy, thermal degradation has been investigated by cone calorimetry and thermogravimetric analysis (TGA), and the products of degradation have been studied with TGA/FT-IR and gas chromatography/mass spectrometry (GC/MS). There are no marked differences in the degradation products of the polymer and its nanocomposites, but the degradation of the nanocomposite occurs at higher temperatures. The most likely explanation is that poly(methyl methacrylate) degrades by only a single route, so the clay cannot promote one pathway at the expense of another. This observation bears important implications for the barrier mechanism, which is currently used to explain the reduction in the peak heat release rate of nanocomposites. Copyright (C) 2006 John Wiley & Sons, Ltd.