Cellulose acetate was reacted in different ratios with poly[dimethyl(methyl-H) siloxane] containing 25 mol% Si-H side groups along the chain. A dehydro-coupling reaction between Si-H and C-OH groups occurred in presence of Karstedt's catalyst, leading to the formation of Si-O-C bond, as proved by FTIR spectra, thus crosslinking the cellulose derivative. The networks were processed as films by casting before the end of the reaction and were investigated by different techniques to emphasize the morphology, thermal, dielectric and surface properties developed in correlation with the ratio between the two involved components (cellulose and siloxane derivatives). A decrease of the dielectric constant values of cellulose acetate was noticed throughout the studied frequency and temperature range as a result of crosslinking.