An ethylene-ethyl acrylate-maleic anhydride copolymer (EEAMA) is grafted with aminopropyl polydimethylsiloxane (PDMS) via melt reactive mixing at 140 degrees C. The materials produced split into two components based on their solubility in acetone. The acetone soluble material is highly enriched in PDMS, whereas the insoluble material contains levels of PDMS that are lower than the proportions added to the reaction mixture. It was found that for all reaction mixtures the PDMS content in the acetone insoluble solids increases with mixing time. Molecular weight distributions of materials become narrower as the amount of PDMS increases. Rheological testing shows that the level of PDMS in the mixtures and the presence of the acetone soluble fractions give rise to significant changes in the complex viscosity and elastic moduli for the polymers. (c) 2006 Wiley Periodicals, Inc.