The present invention relates to superabsorbent polymer particles having functionalizers covalently bound to the surface of precursor superabsorbent polymer particles.The functionalizers of the present invention comprise a grafting unit with a radiation activatable group and a functional unit covalently bound to the grafting unit. The grafting unit is bound to an aliphatic C--H group comprised at the surface of the precursor superabsorbent polymer particle. The functional unit comprises chemical structures which are not present in the precursor superabsorbent polymer particle. These functional units add an additional function to the precursor suberabsorbent polymer particle or modifying an existing function of the precursor superabsorbent polymer particle.Moreover, the invention relates to a process for making these superabsorbent polymer particles.