Covalent functionalization of pentadecane-decorated multiwalled carbon nanotubes (MWCNTs) has been studied as a model compound approach for the grafting of poly(ethylene-co-1-octene) onto MWCNTs by reactive extrusion. It was accomplished through radical addition onto unsaturated bonds located on the MWCNTs' surface using dicumyl peroxide as hydrogen abstractor. It was found that this surface treatment results into the break-up of the native nanotube bundles and increases solubility in various solvents. Raman spectroscopy was utilized to follow the introduction of pentadecane on the MWCNTs' surface; while thermogravirnetric analysis and elemental analysis indicated the extent of this grafting. Pentadecane functionalized MWCNTs were imaged by transmission electronic microscopy showing single long functionalized MWCNTs distinct from the starting pristine bundles. (C) 2009 Elsevier Ltd. All rights reserved.