Synthesis and characterization of reinforced acrylic-based superabsorbents crosslinked with divinylbenzene

A series of superabsorbent polymers were synthesized by an inverse suspension polymerization, with potassium persulfate as the initiator, Span60 as the dispersant, and N,N'-methylene bisacrylamide (BIS) and divinylbenzene (DVB) as multiple crosslinkers. The synthesis conditions, including the amount of dispersant, concentration of crosslinkers, oil-to-water phase ratio (O/W) of the polymerization system, total monomer concentration, and acrylamide (AM) content were studied. The results indicated that there were optima for the following properties: BIS crosslinker concentration (0.075 wt %), O/W (3:1), total monomer concentration (37.5 wt %), and AM content (5 wt %). In addition, the particle size had a significant influence on the absorption speed, and the absorption speed increased with decreasing particle size. In comparison with the conventional sample crosslinked only by BIS, the superabsorbent with the same particle size but crosslinked by multiple crosslinkers had the higher absorption rate because of surface crosslinking. It also showed that the salt resistance and antihydrolyzing property of the superabsorbent crosslinked by multiple crosslinkers (BIS and DVB) were enhanced, which was also attributed to surface crosslinking by DVB. (c) 2006 Wiley Periodicals, Inc.