Preparation,swelling, and stimuli‐responsive characteristics of superabsorbent nanocomposites based on carboxymethyl cellulose and rectorite

Utilization of naturally available raw materials for the fabrication of eco‐friendly functional materials has long been desired. In this work, a series of superabsorbent nanocomposites were prepared by radical solution copolymerization of sodium carboxymethyl cellulose (CMC), partially neutralized acrylic acid (NaA), and rectorite (REC) in the presence of initiator ammonium persulfate (APS) and crosslinker N,N'‐methylene‐bis‐acrylamide (MBA). The optimal reaction variables including the mass ratio of acrylic acid (AA) to CMC, MBA concentration, and REC content were explored. FTIR spectra confirmed that NaA had been grafted onto CMC and REC participated in polymerization. REC was exfoliated and uniformly dispersed in the CMC‐g‐PNaA matrix without agglomeration as shown by XRD, TEM, and SEM analysis. The thermal stability, swelling capabilities, and rate of the nanocomposites were improved after introducing REC, and the gel strength greatly depended on the concentration of crosslinker MBA. The nanocomposite showed excellent responsive properties and reversible On–Off switching characteristics in various saline, pH, and hydrophilic organic solvent/water solutions, which provided great possibility to extend the application domain of the superabsorbent nanocomposites such as drug delivery system. Copyright © 2010 John Wiley & Sons, Ltd.