Synthesis, Microcharacterization, and Viscosity Profiling of Alginate-Graft-Polyacrylamide Superabsorbent Hydrogels

International Journal of Chemistry | Vol. 10, No. 12, December 2019 | pp. 89–96

DOI: 10.46882/2019/IJC/000134

Article Type: Original Research Paper

Title: Synthesis, Microcharacterization, and Viscosity Profiling of Alginate-Graft-Polyacrylamide Superabsorbent Hydrogels

Names of Authors: J. K. Mensah¹, S. K. Roy²*

Authors’ Affiliations:
¹Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
²Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, India.

Abstract: The development of durable biopolymeric hydrogel networks is essential for agricultural soil water retention and controlled agrochemical delivery due to the requirement for specific structural coordination sites. This study describes the chemical synthesis and rheological optimization of a hybrid hydrogel fabricated via the free-radical graft copolymerization of acrylamide onto a high-viscosity sodium alginate backbone. The grafting reaction was initiated using potassium persulfate (KPS) and crosslinked via N,N'-methylenebisacrylamide (MBA) under optimized atmospheric conditions. Structural networks and morphology features were characterized using FT-IR spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Swelling kinetics were evaluated as a function of time, pH, and saline concentration. The hydrogel showed highly responsive pH-dependent swelling profiles, achieving a maximum water absorption capacity of 410 g/g at pH 7.4 due to structural carboxylate ionizations causing intermolecular chain repulsions. Rheological analysis confirmed strong non-Newtonian shear-thinning characteristics with a storage modulus (G') that remained constant up to 80°C. Batch adsorption tests showed high affinity for divalent lead and copper ions, matching the Langmuir isotherm with monolayer capacities of 72.4 mg/g and 85.6 mg/g at 298 K, confirming high remediation potential.

Keywords: Sodium alginate; Acrylamide; Graft copolymerization; Hydrogel; Viscosity profiling; Heavy metal adsorption

Manuscript Timeline: Received: March 15, 2019; Revised: April 22, 2019; Accepted: May 20, 2019; Published: December 08, 2019.

Citation: Mensah, J. K., & Roy, S. K. (2019). Synthesis, Microcharacterization, and Viscosity Profiling of Alginate-Graft-Polyacrylamide Superabsorbent Hydrogels. International Journal of Chemistry, 10(12), 89–96.

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