The present invention relates to a method for post-modification of a macroporous polymeric support comprising one or more unreacted double bonds, which method includes the steps of contacting the support with a liquid comprising a grafting compound; and initiating a free radical reaction in the mixture obtained, wherein the grafting compound is comprised of a double bond as a reactive group coupled to a linear or cyclic chain of carbon. The grafting compound can be illustrated with vinyl ethers and/or styrene and styrene derivatives.