Patent ID: 7700663

Claim:
A superabsorbent polymer comprising: a. particles selected from the group consisting of granules, flakes, spheres, powders, platelets, and beads, the particles having a surface and a plurality of carboxyl groups present at the surface, the carboxyl groups configured to chemically react with a surface cross-linker; and b. the reaction product of one or more of the carboxyl groups and a radiation activatable surface cross-linker, wherein the reaction product is produced by exposing the superabsorbent polymer and the radiation activatable surface cross-linker to electromagnetic radiation, the radiation activatable surface cross-linker comprising at least two radiation activatable groups R, the at least two radiation activatable groups R being covalently bound to each other or to at least one spacer group S, the spacer group S being selected from the group consisting of an organic group with a molecular weight of up to about Mw=10000, and a polymeric group with a molecular weight of up to about Mw=1000000, wherein the radiation activatable groups R are the same or different and are selected from the group consisting of acetophenone, benzophenone, anthraquinone, xanthone, thioxanthone, camphorquinone, terphthalophenone, benzyl, fluorenone, α-ketocoumarin, and their derivatives, wherein the acetophenone derivatives include reaction products comprising at least two acetophenone groups and the benzophenone derivatives include at least two benzophenone groups.