HYDROGEL COMPOSITES AND SUPERPOROUS HYDROGEL COMPOSITES HAVING FAST SWELLING, HIGH MECHANICAL STRENGTH, AND SUPERABSORBENT PROPERTIES

摘要

A superporous hydrogel composite is formed by polymerizing one or more ethylenically-unsaturated monomers, and a multiolefinic cross-linking agent, in the presence of particles of a disintegrant and a blowing agent. The disintegrant, which rapidly absorbs water, serves to greatly increase the mechanical strength of the superporous hydrogel and significantly shortens the time required to absorb water and swell. Superporous hydrogel composites prepared by this method have an avera ge pore size in the range of 10 .mu.m to 3,000 .mu.m. Preferred particles of disintegrant include natural and synthetic charged polymers, su ch as cross-linked sodium carboxymethylcellulose, cross-linked sodium starch glycolate, and cross-linked polyvinylpyrrolidone. The blowing agent is preferably a compound that releases gas bubbles upon acidification, such as NaHCO3. Improved hydrogel composites formed without a blowing agent are also provided.