Superabsorbent polymer with improved permeability and absorption rate using hollow glass microspheres

Abstract

Itaconic acid-vinyl sulfonic acid based super absorbent polymer (SAP) was synthesized by aqueous solution polymerization using ammonium persulfate as the initiator, tetra (ethylene glycol) diacrylate as the internal crosslinking agent, and sodium hydroxide as the neutralizing agent. Surface-crosslinking was introduced to improve the low absorbency under load of the itaconic acid-based SAP. Hollow glass microspheres were added during surface-crosslinking to improve the absorption properties and permeability of the SAP. Hollow glass microspheres increased the specific surface area of SAP and acted as an incompressible filler resulting in the improvement of gel strength and the relief of gel blocking by preventing adhesion between SAP particles. The surface-crosslinked SAP with 2 wt% hollow glass microspheres showed the highest permeability and absorbency under load. The absorption rate of the synthesized material was also increased.