| Abstract: | A sodium starch sulfate–based superabsorbent was synthesized to improve water and saline absorbencies. A sodium starch sulfate with high degree of substitution was synthesized by the reaction of starch gelatinized with dimethyl acetamide (DMAc)/lithium chloride (LiCl) and a dimethyl formamide–sulfur trioxide (DMF–SO3) complex. The sodium starch sulfate was then graft‐polymerized with acrylonitrile and the nitrile groups of the sodium starch sulfate‐g‐polyacrylonitrile were converted to a mixture of hydrophilic carboxamide and carboxylate groups by alkaline hydrolysis. The hydrolyzed sodium starch sulfate‐g‐polyacrylonitrile copolymer exhibited improved water and saline absorbencies compared with that of existing starch‐based superabsorbents, resulting from the presence of sulfate groups. The maximum water and saline absorbencies of the sodium starch sulfate–based superabsorbent were 1510 and 126.4 g/g, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1423–1430, 2001 |
