Study on the synthesis and application of salt‐resisting polymeric hydrogels

A kind of hydrogel of semi‐2 interpenetrating polymer network (IPN) consisting of poly(sodium acrylate) (PSA) and poly(vinyl alcohol) (PVA), i.e. semi‐2 IPN PVA/PSA hydrogel, was synthesized by interpenetrating polymerization of sodium acrylate and N,N′‐methylene bisacrylamide into a solution of PVA, using potassium persulfate and sodium bisulfite as initiators. The synthetic conditions affecting the properties of the resulting hydrogel and optimal conditions were investigated, while the resulting IPN hydrogel used as an agent for holding‐water was employed in the planting of trees in an arid soil containing a higher amount of saline. Experimental results indicate that the semi‐2 IPN PVA/PSA hydrogel has an absorbency of 700–800 and 70–90 ml/g for distilled water and saline solution, respectively, as well as showing a better salt‐resistance and water‐absorbing rate compared to polymeric hydrogels based on PSA due to the introduction of the PVA segment. The results showed the surviving ratio of the planted saplings could reach 100% and be raised to 70% compared with those without hydrogel.