This invention relates to a process to produce a functionalized polymer comprising: a) contacting an iodine modified aromatic polymer with an oxidizing agent to obtain an iodonium salt of the aromatic polymer; b) contacting the iodonium salt of the aromatic polymer with a polymer having internal or terminal unsaturation(s); and c) obtaining a functionalized polymer from the polymer having internal or terminal unsaturation(s) wherein the functionalized polymer has an Mn less than the Mn of the polymer having internal or terminal unsaturation(s) and the functionalized polymer has an acid number higher than the acid number of the polymer having internal or terminal unsaturation(s).