Recent experimental data of Cohen Addad and Frebourg on the adsorption of polybutadiene chains on the ISAF carbon black from bulk were compared with the polymer-filler gel formation theory. A very good agreement was obtained and the resulting parameter-values were similar to those recently determined for the SBR-ISAF black system. This lends support to the model upon which the theory is based : random adsorption of polymer segments, filler particles acting as a polyfunctional crosslinking agent. The Cohen Addad-Frebourg theoretical treatment of polybutadiene adsorption on carbon black (polymer chains bifunctional, dangling chains partially eliminated by the solvent) is critically reviewed.