Effect of intercalated reactive mica on water absorbency for poly(sodium acrylate) composite superabsorbents

A series of superabsorbents based on sodium acrylate (NaA), mica (MI), and N,N′-methylene-bis-acrylamide (NMBA) were prepared by inverse suspension polymerization. The influences of the type and content of mica such as pure K⁺-MI and intercalated-MI (IMI) in the composite gels on the water absorbency and the initial absorption rate in deionized water and salt solutions were investigated. Results showed that the water absorbency and initial absorption rate gradually decrease with increasing amounts of pure K⁺-MI and intercalated-MI. In addition, the water absorbency and initial absorption rate for the gels prepared by intercalated-MI were lower than those prepared by pure K⁺-MI.