Study of different methods to induce crosslinking of polyacrylamide for agriculture process

Document Type : Research Article


1 Department of Polymers, Industrial Irradiation Division, National Centre for Radiation Research and Technology (NCRRT), Atomic Energy Authority, Nasr City, Cairo 11371, Egypt

2 Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt

3 Environmental Department, Egyptian Airports Company, Cairo, Egypt


The present study describes two different methods for the preparation of superabsorbent polyacrylamide (PAAm) hydrogels for application in farming of sandy soil. The two methods were employed to induce the crosslinking of the polymer matrix. In the first method a PAAm paste was exposed to gamma rays, while in the second method the polymer was thermally treated in the solid phase. Crosslinked PAAm hydrogel samples prepared by both methods were characterized by gel content, water absorbance, Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The parameters affecting the gel content, including the irradiation dose and temperature, were investigated. The obtained results suggested that the gel content of the PAAm hydrogel crosslinked by radiation and thermal treatments increases as the irradiation dose and temperature increased. Furthermore, the results indicated that the water absorbance reaches the maximum values at an irradiation dose of 30 kGy and a temperature of 120 ºC. SEM showed that the synthesized hydrogels have a porous morphology. The PAAm hydrogel samples were loaded with urea and their release behavior was examined in water. Finally, the effect of hydrogels on the growth of beans (Vicia faba L.) was studied. The radiation crosslinked samples displayed better stability during the farming period and enhanced plant growth in comparison with the samples crosslinked by thermal treatment.

Graphical Abstract

Study of different methods to induce crosslinking of polyacrylamide for agriculture process


  • Preparation of superabsorbent polyacrylamide (PAAm) hydrogels radiation or thermal.
  • Application of PAAm hydrogels in farming of sandy soil.
  • The PAAm hydrogel samples were loaded with urea and their release behavior was examined in water.


[1] J.V.R.S. Souzaa, J.C.C. Saada, R.M. Sánchez-Romána, L. Rodríguez-Sinobas, No-till and direct seeding agriculture in irrigated bean: Effect of incorporating crop residues on soil water availability and retention, and yield, Agr. Water Manag. 170 (2016) 158-166.
[2] E.M. Ahmed, Hydrogel: Preparation, characterization, and applications, A review, J. Adv. Res. 6 (2015) 105-121.
[3] A. Pourjavadi, R. Soleyman, G.R. Bardajee, Novel superabsorbent hydrogel based on natural hybrid backbone: Optimized synthesis and its swelling behavior, Bull. Korean Chem. Soc. 30 (2009) 2680-2686.
[4] X.N. Shi, W.B. Wang, A.Q. Wang, Effect of surfactant on porosity and swelling behaviors of guar gum-g-poly(sodium acrylate-costyrene)/attapulgite superabsorbent hydrogels, Colloid. Surface B, 88 (2011) 279-286.
[5] A. Pourjavadi, H. Hosseinzadeh, Synthesis and Properties of Partially Hydrolyzed Acrylonitrile-co -Acrylamide Superabsorbent Hydrogel. B. Kor. Chem. Soc. 31 (2010) 3163-3172.
[6] K.M. Raju, M.P. Raju, Synthesis and swelling properties of superabsorbent copolymers, Adv. Polym. Tech. 20 (2001) 146-154.
[7] S.W. Ali, S.A.R.J. Zaidi, Synthesis of copolymeric acrylamide/potassium acrylate hydrogels blended with poly(vinyl alcohol): Effect of crosslinking and the amount of poly(vinyl alcohol) on swelling behavior, Appl. Polym. Sci. 98 (2005)1927-1931.
[8] L. Xu , X. Zhang, C. Zhu, Y. Zhang, C. Fu, B. Yang, L. Tao, Y. Wei, Nonionic polymer cross-linked chitosan hydrogel: preparation and bioevaluation, J Biomat Sci-Polym Ed. 24 (13) (2013)1564-1574.
[9] X. Zhang, K. Wang, M. Liu, X. Zhang, L. Tao, Y. Chen, Y. Wei, Polymeric AIE-based nanoprobes for biomedical applications: recent advances and perspectives, Nanoscale, 7 (2015)11486-11508.
[10] N. Seetapan, J. Wongsawaeng, S. Kiatkamjornwong, Gel strength and swelling of acrylamide-protic acid superabsorbent copolymers, Polym. Advan. Technol. 22 (2011) 1685-1695.
[11] B. Yang, Y. Zhang, X. Zhang, L. Tao, S. Lia, Y. Wei, Facilely prepared inexpensive and biocompatible self-healing hydrogel: a new injectable cell therapy carrier, Polym. Chem. 3 (2012) 3235-3238.
[12] D. Valade, L.K. Wong, Y. Jeon, Z. Jia, M.J. Monteiro, Materials and devices containing hydrogel-encapsulated cells, J. Polym. Sci. A1, 51 (2013) 129-138.
[13] M. Sairam, V.R. Babu, B. Vijaya, K. Naidu, T.M. Aminabhavi, Encapsulation efficiency and controlled release characteristics of crosslinked polyacrylamide particles, Int. J. Pharm. 320 (2006) 131-136.
[14] H.A. Abd El-Rehim, Swelling of radiation crosslinked acrylamide-based microgels and their potential applications, Radiat. Phys. Chem. 74 (2005) 111-117.
[15] B. Bolto, T. Tran, M. Hoang, Z.L. Xie, Crosslinked poly(vinyl alcohol) membranes, Prog. Polym. Sci. 34 (2009) 969-981.
[16] T. Puspasari, N. Pradeep, K.V. Peinemann, Crosslinked cellulose thin film composite nanofiltration membranes with zero salt rejection, J. Membrane Sci. 491 (2015) 132-137.
[17] M. Shafiq, A. Sabir, A. Islam, S.M. Khan, S.N. Hussain, M.T.Z.Z. Butt, T. Jamil, Development and performance characteristics of silane crosslinked poly(vinyl alcohol)/chitosan membranes for reverse osmosis, J. Ind. Eng. Chem. 48 (2017) 99-107.
[18] X. Jin, L. Li, R. Xu, Q. Liu, L. Ding, Y. Pan, C. Wang, W. Hung, K. Lee, K., T. Wang, Effects of thermal cross-linking on the sructure and property of asymmetric membrane prepared from the polyacrylonitrile, Polymers-Basel, 10 (2018) 539.
[19] A.A. Ibrahim, B.Y. Jibril, Controlled release of parafin wax/rosin-coated fertilizers, Ind. Eng. Chem. Res. 44 (2005) 2288-2291.
[20] R. Liang, H. Yuan, G. Xi, Q. Zhou, Synthesis of wheat straw-g-poly(acrylic acid) superabsorbent composites and release of urea from it, Carbohyd. Polym. 77 (2009) 181-187.
[21] M. Eid, In vitro release studies of vitamin B12 from poly N-vinyl pyrrolidone/starch hydrogels grafted with acrylic acid synthesized by gamma radiation, Nucl. Instrum. Meth. B, 266 (23) (2008) 5020-5026.
[22] A.K. Bajpai, A. Giri, Water sorption behaviour of highly swelling (carboxy methylcellulose-g-polyacrylamide) hydrogels and release of potassium nitrate as agrochemical, Carbohyd. Polym. 53 (2003) 271-279.
[23] A.I. Raafat, M. Eid, M.B. El-Arnaouty, Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications Nucl. Instrum. Meth. B, 283 (2012) 71-76.
[24] M. Hashem, S. Sharaf, M.M. El-Hady, A. Hebeish, Synthesis and characterization of novel carboxymethylcellulose hydrogels and carboxymethyl cellulolse-hydrogel -ZnO-nanocomposites, Carbohyd. Polym. 95 (2013) 421-427.
[25] S. Kiatkamjornwong, Superabsorbent polymers and superabsorbent polymer composites, ScienceAsia, 33 Supplement 1 (2007) 39-43.
[26] W. Luo, W. Zhang, P. Chen, Y. Fang, Synthesis and properties of starch grafted poly[acrylamide-co-(acrylic acid)]/montmorillonite nanosuperabsorbent via γ-ray irradiation technique, J. Appl. Polym. Sci. 96 (2005) 1341-1346.
[27] K. Kabiri, H. Omidian, S.A. Hashemi, M.J. Zohuriaan-Mehr, Synthesis of fast-swelling superabsorbent hydrogels: effect of crosslinker type and concentration on porosity and absorption rate, Eur. Polym. J. 39 (2003) 1341-1348.
[28] D.R. Biswal, R.P. Singh, Characterisation of carboxymethyl cellulose and polyacrylamide graft copolymer, Carbohydr. Polym. 57 (2004) 379–387.
[29] W.M. Leung, D. E. Axelson, J. D. Van Dyke, Thermal degradation of polyacrylamide and poly(acrylamide-co-acrylate). J. Polym. Sci. A, 25 (1987) 1825-1846.
[30] R.S. Tomar, I. Gupta, R. Singhal, A.K. Nagpal, Synthesis of poly (acrylamide co-acrylic acid)-based superabsorbent hydrogels by gamma radiation: study of swelling behavior and network parameters, Des. Monomers Polym. 10 (2007) 49-66.
[31] D. Swantomo, R. Rochmadi, K.T. Basuki, R.Sudiyo, Synthesis and characterization of graft copolymer rice straw cellulose-acrylamide hydrogels using gamma irradiation, Atom Indonesia, 39 (2013) 57-64.
[32] S. Kim, G. Iyer, A. Nadarajah, J.M. Frantz, A.L. Spongberg, Polyacrylamide hydrogel properties for horticultural applications, Int. J. Polym. Anal. Ch. 15 (2010) 307-318.
[33] L. Chen, X. Qiu, M. Deng, Z. Hong, R. Luo, X. Chen, X. Jing, The starch grafted poly(L-lactide) and the physical properties of its blending composites, Polymer, 46 (2005) 5723-5729.
[34] L. Chen, X. Qiu, Z. Xie, Z. Hong, J. Sun, X. Chen, X. Jing, Poly (l-lactide)/starch blends compatibilized with poly (l-lactide)-g-starch copolymer, Carbohyd. Polym. 65 (2006) 75-80.
[35] H.B. Hopfenberg, K.C. Hsu, Swelling-controlled, constant rate delivery systems, Polym. Eng. Sci. 18 (1978) 1186-1191.
[36] S.W. Kim, Y.H. Bae, T. Okano, Hydrogels: Swelling, drug loading, and release, Pharm. Res. 9 (1992) 283-290.
[37] A. Nadler, E. Perfect, B. D Kay, Effect of polyacrylamide application on the stability of dy and wet aggregates, Soil Sci. Soc. Am. J. 60 (1996) 555-561.
[38] R.E. Sojka, R.D. Lentz, C.W. Ross, T.J. Trout, D.L. Bjorneberg, Aase, J. K. Polyacrylamide effects on infiltration in irrigated agriculture, J. Soil Water Conserv. 53 (1998) 325-331.
[39] P. Jobin, J. Caron, P. Bernier, B.J. Dansereau, Impact of two hydrophilic acrylic-based polymers on the physical properties of three substrates and the growth of Petunia xhybrida "Brilliant Pink", J. Am. Soc. Hortic. Sci. 129 (2004) 449-457.
[40] H. A. Abd El-Rehim, E. A. Hegazy, H. L. Abd El-Mohdy, Radiation synthesis of hydrogels to enhance sandy soils water retention and increase plant performance, J. Appl. Polym. Sci. 93 (2004) 1360-1371.
[41] A.I. Al-Humaid, A.E. Moftah, Effects of hydrophilic polymer on the survival of buttonwood seedlings grown under drought stress, J. Plant Nutr. 30 (2007) 53-66.