Carboxymethyl cellulose-based semi-IPN hydrogel nanocomposite with improved physicochemical and mechanical properties

Sulfonated carboxymethyl cellulose-g-poly (acrylic acid-co-acrylamide)/polyvinyl alcohol/ montmorillonite (SCMC-g-p(AA-co-AAm)/PVA/MMT) semi interpenetrating polymer network (semi-IPN) as superabsorbent nanocomposite hydrogel was synthesized by free-radical graft copolymerization method in an aqueous solution. Taguchi experimental design approach was used to optimize the synthesis condition of the hydrogel. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the successful grafting reaction of acrylate-based monomers onto SCMC and the presence of MMT and PVA in the hydrogel nanocomposite network. Scanning electron microscope (SEM) images of MMT containing superabsorbent nanocomposite hydrogel showed that the addition of MMT into the polymeric matrix of hydrogel forms porous structures within the hydrogel network. Superabsorbent nanocomposite hydrogel containing MMT showed more excellent equilibrium swelling capacity (714 g/g) than the neat hydrogel (530 g/g). Swelling kinetic results indicated that superabsorbent nanocomposite swells faster than the neat hydrogel. The Water absorption capacity of the hydrogels under different loads (psi 0.3, psi 0.6 and psi 0.9) was investigated. Also, the swelling behavior of the hydrogels in various pH and saline solutions was assessed. The good properties of synthesized superabsorbent nanocomposite suggests that it is proper candidate to use in agriculture industry.