Collagen-g-poly(Sodium Acrylate-co-Acrylamide)/sodium montmorillonite superabsorbent nanocomposites: synthesis and swelling behavior

Abstract

Nanocomposite superabsorbents were synthesized by graft copolymerization of mixture of acrylamide (AAm) and acrylic acid (AA) onto collagen using potassium persulfate (KPS) as a free radical initiator and methylenebisacrylamide (MBA) as a crosslinker. Nanoclay sodium montmorillonite (MMt) was introduced as filler into superabsorbent. The chemical structure of the Collagen-g-poly(Sodium Acrylate-co-Acrylamide)/MMt nanocomposite was characterized by means of FTIR spectroscopy, XRD patterns, and TGA thermal methods. Morphology of the sample was examined by scanning electron microscopy (SEM). The effects of reaction variables were systematically optimized to achieve a superabsorbent with swelling capacity as high as possible. Under the optimized conditions concluded, the maximum swelling capacity in distilled water was 950 g/g. Dewatering of nanocomposite and clay-free superabsorbent revealed that inclusion of nanoclay into superabsorbents can improve water retention of superabsorbent under heating. The swelling ratio in various salt solution and kinetic of dewatering was also determined and additionally, the swelling of nanocomposite superabsorbent was measured in solution with pH ranged 1–13. The synthesized nanocomposite exhibited a pH-responsive characteristic.