Porous structure of an absorbent polymer

Abstract

A porous structure of a water-swellable, water-insoluble polymeric material which porous structure possesses improved free swell capacity and is able to demonstrate said improved free swell capacity when in contact with an absorbent material such as a cellulosic fibrous web. Also disclosed is a method of making such a porous polymeric structure. The method comprising the steps of forming an oil-in-water suspension, wherein the water phase contains a water-soluble monomer and a crosslinking agent and the oil phase is a volatile organic compound having a boiling point greater than the boiling point of water. The monomer present in the water phase is polymerized to form a polymeric material having dispersed therein the oil phase. The resultant polymeric material is then dried at a temperature above the boiling point of water, such that the volatile organic compound volatilizes thereby forming pores in the polymeric material, which pores have a diameter of at least about 20 microns. The polymeric material is at least partially dried before the organic compound volatilizes so that the polymeric material possesses sufficient structural integrity to maintain the openness of the chambers.