Novel Degradable Superabsorbent Materials of Silicate/Acrylic-Based Polymer Hybrids

Novel superabsorbent materials, inorganic-organic hybrids, were synthesized by polymerizing acrylic acid or acrylamide with sodium silicate without any other crosslinking agent. The crosslinking bonds of Si - O - C form through the reaction of carboxyl groups with silanol groups (Si - OH) existing in reaction system. Results of FTIR, swelling, and degrading experiments show that the crosslinking degree increased as the mol ratio of silicate increased in a certain range. The hybrids possess the properties of high absorbency and high absorption rate in both distilled water and normal saline solution. Because of the hydrolysis of Si - O - C bonds in aqueous solution, the hybrid hydrogels can degrade in days, and maybe beneficial to environment protection. This property is quite different from those superabsorbent polymer crosslinked with organic crosslinking agent. By monitoring the temperature of the reaction system, sodium silicate was also found to facilitate the trommsdorff effect in polymerization process. © 2003 Wiley Periodicals, Inc.