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 polyeth ylene glycol diglycidyl ethers (PEGDGE) with different degrees of polymeriz ation under different conditions. A crosslinking agent with longer chain le ngth might be advantageous for preparing a water absorbent with high water retention, and water retention could be improved at lower molar ratio of th e crosslinking agent to the glucose unit. Isolation of carboxymethylated LB KP before crosslinking was advantageous for higher water absorbence. A wate r absorbent with a water retention value of as high as 500 times its weight was obtained.