Composites of active carbon in a polymeric matrix composed of polyethylene oxide (PEO) and polyethylene glycol (PEG) having different molecular weight distributions were obtained by melt mixing. Characterization of the amount of bound polymer in the whole range of composition for the polymeric matrix has been performed after dissolution of the matrix in water. Size exclusion chromatography of the solution has been used to determine the composition of the polymeric bound layer. It has been shown that in these conditions of mixing, the amount of bound polymer slightly decreases from a pure PEG to a pure PEO matrix. Furthermore, PEO is preferentially bound to the active carbon. A simple model is used to show that bonding occurs preferentially by monomeric units rather than by chain ends. (c) 2006 Wiley Periodicals, Inc.