Nanocomposites at elevated temperatures: migration and structural changes

The possible effect of temperature stability of organic layered silicates (OLSs) on the structure and flammability behavior of polymer/montmorillonite (MMT) nanocomposites has been discussed in a previous publication. Above 200 degrees C, the OLS begins to decompose, and the nanocomposite structure is gradually destroyed even before pyrolysis and combustion. Data on the decomposition of polymer/OLS mixtures upon isothermal thermogravimetric analysis (TGA) experiments are presented, and include rates and energies of activation at a range of temperatures from 200 to 400 degrees C. Decomposition of OLSs in the presence of polymer is discussed in view of the decomposition of clay, pristine surfactant, and OLS. Accumulation of clay by migration to the surface of samples at a range of temperatures is indicated by X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) measurements on the isothermally heated samples. Mechanistic considerations concerning changes in the structure of the nanocomposite, the decomposition of OLS, and migration of clay will be presented. Copyright (C) 2006 John Wiley & Sons, Ltd.