Preparation and properties of a salt-resistant superabsorbent polymer

Crosslinked sodium polyacrylate was prepared by solution polymerization with N,N-methylene-bisacrylamide (bisAM) as crosslinking agent; it was subsequently surface-crosslinked by ethylene glycol diglycidyl ether (EGDE) and then was modified with inorganic salt to obtain a superabsorbent with water absorbency in 0.9 wt % NaCl aqueous solution at atmosphere and applied pressure (P approximate to 2 x 10(3) Pa) of 55 and 20 g.g(-1), respectively. Moreover, it also had excellent hydrogel strength. The effects of reaction temperature, reaction time, neutralization degree (ND) of acrylic acid, amount of initiator, crosslinking agent, and surface-crosslinking agent, mass ratio of inorganic salt to initial superabsorbent, molar ratio of sodium aluminate (NaAlO2) to potassium dihydrogen hyphosphate (KH2PO4) on water absorbency (WA) in 0.9 wt % NaCl aqueous, and the hydrogel modulus were investigated and optimized. (C) 2004 Wiley Periodicals, Inc.