Preparation and Properties of High Water-absorbent Poly(Sodium Acrylate)

Preparation of high water absorbent poly(sodium acrylate) was carried out by inverse suspension polymerization in cyclohexane with Span-60 as suspension stabilizer,potassium persulfate as initiator and N,N′ methylene bisacrylamide as crosslinking agent.The results showed that the concentration of crosslinking agent was the most important factor affecting the water absorbency of synthesized resins.The maximum absorption capacity appeared when the concentration of crosslinking agent was about 0.018%,and the absorption capacity of the resin prepared at 65 ℃ reached 500 g/g while the concentration of initiator was 0.15%.The test of water absorbing rate and water retention power of high water absorbent resins indicated that the speed of water absorption was high at the beginning and leveled off with time.Furthermore,the absorbed water lost only 17% in 2.5 h at 84 ℃.