Development of high-retention water absorbent from cellulosic materials: water absorbent from bleached kraft pulp

This paper describes the synthesis of high-retention water absorbents from kraft pulp and examination of their properties. A bleached kraft pulp from mixed hardwoods (LBKP) was carboxymethylated, then crosslinked with polyethylene glycol diglycidyl ethers (PEGDGE) with different degrees of polymerization under different conditions. A crosslinking agent with longer chain length might be advantageous for preparing a water absorbent with high water retention, and water retention could be improved at lower molar ratio of the crosslinking agent to the glucose unit. Isolation of carboxymethylated LBKP before crosslinking was advantageous for higher water absorbence. A water absorbent with a water retention value of as high as 500 times its weight was obtained.