Inverse gas chromatography (IGC) has been used to investigate the surface properties of two calcined kaolins and of polyethylene composites containing calcined kaolin. The results reveal differences in the two kaolins that were not found in XPS spectra nor in their influence on the melting behaviour of the polymer. The kaolin that had a markedly higher surface energy and stronger Lewis acid behaviour was found to shower greater photooxidative degradation in accelerated weathering tests. This novel application of IGC derived surface characterisation of solids further extends the usefulness of the method in this type of work. (C) 2004 Published by Elsevier Ltd.