ABSTRACT:
Polyacrylic acid hydrogels were successfully synthesised using NO2 gas in aqueous solution as initiator and N, N-methylenebisacrylamide (BAM) as cross-linker at a mild concentration at 50°C. After 2 to 4 hours, the polymerising mixture was transformed into a glassy, flexible, scabby and spongy mass which was taken out and washed repeatedly to remove soluble and unreacted material and then dried. When the dried sample of polymer hydrogels so formed was subjected to alkaline saponification, the hydrolysed polyacrylic hydrogels was found up to 150 times their mass. The effects of monomer concentration, cross-linker density, NaOH concentration during saponification, initiator concentration, temperature of polymerisation, pH of the medium were studied. The formed hydrogels also have a reversible swelling behaviour. Such type of hydrogel has various applications in hygiene products, agriculture, drug delivery systems, pharmaceuticals, biomedical, tissue engineering, and wound dressing etc. The study of temperature effects reveals that PAA hydrogels often display high swelling, leading to deformation and deswelling, showing weakened mechanical strength property of the hydrogels. The thermogravimetric analysis (TGA) also reveals the same. FTIR spectroscopy was carried out to show the chemical structure of the hydrogels. Morphology of the hydrogels was also studied by FESEM.
Cite this article:
Reena Bhadani, Kumari Neetu Singh. Eco Friendly Polymerisation Route for Acrylic Acid via NO2 gas in aqueous medium for Hydrogel Synthesis. Asian Journal of Research in Chemistry.2026; 19(4):304-0. doi: 10.52711/0974-4150.2026.00047
Cite(Electronic):
Reena Bhadani, Kumari Neetu Singh. Eco Friendly Polymerisation Route for Acrylic Acid via NO2 gas in aqueous medium for Hydrogel Synthesis. Asian Journal of Research in Chemistry.2026; 19(4):304-0. doi: 10.52711/0974-4150.2026.00047 Available on: https://www.ajrconline.org/AbstractView.aspx?PID=2026-19-4-4
5. REFERENCES:
1. Omidian, H., Rocca, J. G., and Park, K. Advances in superporous hydrogels. Journal of Controlled Release. 2005; 102: 3–12.
2. Fernandez, E., Lopez, D., Lopez-Cabranes, E., and Miljungac, C. Viscosimetric and swelling properties of glucose oxidase–loaded polyacrylamide hydrogel and evaluation of their properties as glucose sensors. Polymer. 2005; 46: 2211–2217.
3. Gupta, P., Vermani, K., and Garg, S. (). Hydrogels from controlled release to pH-responsive agar delivery. Drug Delivery Today. 2002; 10(9): 569–579.
4. Evmenenko, A., Alexe, V., Budova, T., Bunova, A., and Frenkel, S. Swelling-induced changes of polyelectrolyte gels. Polymer. 1999; 40: 2975–2979.
5. Peppas, N. A. (Ed.). (1987). Hydrogels in medicine and pharmacy (Vol. 2). CRC Press.
6. Amende, M., and Peppas, N. A. Transport of ionizable drugs and proteins in crosslinked polyacrylic acid and poly(acrylic acid-co-2-hydroxyethyl methacrylate) hydrogels. Journal of Applied Polymer Science. 1996; 59(4): 673–685.
7. Byrne, M. E., Park, K., and Peppas, N. A. Molecular imprinting within hydrogels. Advanced Drug Delivery Reviews. 2002; 54: 149–161.
8. Grini, G. Recent developments in polysaccharide-based materials used as adsorbents in wastewater treatment. Progress in Polymer Science. 30: 38–70.
9. Gombotz, R., and Hoffman, A. Immobilization of biomolecules and cells on and within synthetic hydrogels. In N. A. Peppas (Ed.), Hydrogels in Medicine and Pharmacy. 1986; 5. CRC Press.
10. Peppas, N. A., and Mikos, A. G. Preparation methods and structure of hydrogels. In N. Peppas (Ed.), Hydrogels in Medicine and Pharmacy. 1986;1. CRC Press.
11. Güven, Ö., Şen, M., Karadağ, E., and Saraydın, D. A review on the radiation synthesis of copolymeric hydrogels for adsorption and separation purposes. Radiation Physics and Chemistry. 1996; 56: 381–386.
12. Denizli, A., Say, R., Garipcan, B., and Patir, S. Methacryloyl-diglycolamic acid functionalized poly (2-hydroxy methylacrylate) beads for UO₂²⁺ removal. Reactive and Functional Polymers. 2004; 58: 123–130.
13. Zhung, A., Asakura, T., and Uchiyama, G. The adsorption mechanism of uranium (VI) from seawater on a macroporous fiber polymeric adsorbent containing amidoxime chelating functional groups. Reactive and Functional Polymers. 2003; 57: 67–76.
14. Dhodapkar, R., Borde, P., and Nandy, T. Superabsorbent polymer in environmental remediation. Global NEST Journa. 2009; 1(2): 223–234.
15. Mahdavinia, G., Pouryavadi, A., Hosseinzadeh, H., and Zohuriaan-Mehr, M. J. Modified chitosan superabsorbent hydrogels from poly(acrylic acid-o-acrylamide) grafted chitosan with salt- and pH-responsive properties. European Polymer Journal. 2004; 40: 1399–1407.
16. Grodzinsky, A., and Grimshaw, P. Electrolytically and chemically controlled hydrogel for drug delivery. In Pulsed and Self‐Regulated Drug Delivery. 1990: 11–27.
17. Cuscler, F., Stokar, M., and Varberg, J. Gels as size-selective extraction solvents. AIChE Journal. 1984; 30: 578–582.
18. Gehrke, S. A., Andrews, G., and Cussler, E. Chemical aspects of gel extraction. Chemical Engineering Science. 1986; 42: 2153–2160.
19. Bhadani, R., and Mitra, U. K. Synthesis and studies on water swelling behaviour of polyacrylamide hydrogels. In Macromolecular Symposia. 2016; 369(1): 30-34.
20. Bhadani, R., Mitra, U. K., and Jayaswal, R. SO₂ initiated polymerization of acrylamide and studies on hydrogels based on resulting polyacrylamide. Asian Journal of Research in Chemistry. 2019; 12(5): 258–262.
21. Bhadani, R., and Mitra, U. K. Asian Journal of Research in Chemistry. 2014; 7: 345.
22. Vogel, A. I. (1969). Quantitative Inorganic Analysis (3rd ed., p. 297). GBLS and Longman.
23. Bhadani, S. N., and Prasad, Y. K. Makromolecular Chemistry. 1980; 181: 1089.
24. Bhadani, S. N., and Sen Gupta, S. K. (1996). In Polymer Material Encyclopedia (p. 22). CRC Press.
25. Zhang J, Qu D, Wang S, Qi S, Zuo H. Structure, Property Optimization, and Adsorption Properties of N,N′-methylenebisacrylamide Cross-Linked Polyacrylic Acid Hydrogels under Different Curing Conditions. Polymers. 2024; 16(14):1990. https://doi.org/10.3390/polym16141990.