Polímeros: Ciência e Tecnologia
Polímeros: Ciência e Tecnologia
Original Article

Coating of urea granules by in situ polymerization in fluidized bed reactors

Fernandes, Bruno Souza; Pinto, José Carlos; Cabral-Albuquerque, Elaine Christine de Magalhães; Fialho, Rosana Lopes Lima

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The main objective of the present work is to produce and characterize urea granules coated with polymers prepared with aqueous solutions of acrylic acid and glycerol. Both coating and drying of urea granules were performed in a fluidized bed reactor. Fourier transform infrared spectroscopy analyses indicated the presence of poly(acrylic acid) and acrylic acid / glycerol copolymers on the granule coating and the formation of chemical bonds between urea and the polymer coating. Scanning electron microscopy images showed that the original and coated urea granules presented different characteristics, reinforcing the idea that coating occurs in the fluidized bed. Finally, rates of urea release showed that the coated granules presented slightly slower rates of urea dissolution in water due to the presence of the coating layer. Therefore, it is shown that it is possible to produce coated urea granules through in-situ polymerization onto the granule surface using a fluidized bed.


acrylic acid; coating; fluidized bed; glycerol; urea


1 Gowariker, V., Krishnamurthy, V. N., Gowariker, S., Dhanorkar, M., & Paranjape, K. (2009). The fertilizer encyclopedia. New Jersey: John & Wiley Sons. 

2 Khan, S., & Hanjra, M. A. (2009). Footprints of water and energy inputs in food production: Global perspectives. Food Policy34(2), 130-140. http://dx.doi.org/10.1016/j.foodpol.2008.09.001

3 Zhao, G. Z., Liu, Y. Q., Tian, Y., Sun, Y. Y., & Cao, Y. (2010). Preparation and properties of macromelecular slow-release fertilizer containing nitrogen, phosphorus and potassium. Journal of Polymer Research17(1), 119-125. http://dx.doi.org/10.1007/s10965-009-9297-4

4 Newbould, P. (1989). The use of nitrogen fertiliser in agriculture: where do we go practically and ecolotically? Plant and Soil115(2), 297-311. http://dx.doi.org/10.1007/BF02202596.

5 Shaviv, A. (2001). Advances in controlled-release fertilizers. Advances in Agronomy71, 1-49. http://dx.doi.org/10.1016/S0065-2113(01)71011-5

6 Islam, M. R., Mao, S., Xue, X., Eneji, A. E., Zhao, X., & Hu, Y. (2011). A lysimeter study of nitrate leaching, optimum fertilisation rate and growth responses of corn (Zea mays L.) following soil amendment with water‐saving super‐absorbent polymer. Journal of the Science of Food and Agriculture91(11), 1990-1997. http://dx.doi.org/10.1002/jsfa.4407. PMid:21480276. 

7 Dave, A. M., Mehta, M. H., Aminabhavi, T. M., Kulkarni, A. R., & Soppimath, K. S. (1999). A review on controlled release of nitrogen fertilizers through polymeric membrane devices. Polymer-Plastics Technology and Engineering38(4), 675-711. http://dx.doi.org/10.1080/03602559909351607

8 Guo, M., Liu, M., Liang, R., & Niu, A. (2006). Granular urea‐formaldehyde slow‐release fertilizer with superabsorbent and moisture preservation. Journal of Applied Polymer Science99(6), 3230-3235. http://dx.doi.org/10.1002/app.22892

9 Tao, S., Liu, J., Jin, K., Qiu, X., Zhang, Y., Ren, X., & Hu, S. (2011). Preparation and characterization of triple polymer‐coated controlled‐release urea with water‐retention property and enhanced durability. Journal of Applied Polymer Science120(4), 2103-2111. http://dx.doi.org/10.1002/app.33366

10 Suherman, S., & Anggoro, D. D. (2011). Producing slow release urea by coating with starch/aciylic acid influid bed spraying. IACSIT International Journal of Engineering and Technology11(6), 77-80. Retrieved in 2017, July 27, from http://citeseerx.ist.psu.edu/viewdoc/versions?doi= 

11 Phillips, J. C. (2011). US Patent No 7,862,642. Washington: U.S. Patent and Trademark Office.

12 Liang, R., & Liu, M. (2007). Preparation of poly (acrylic acid‐co‐acrylamide)/kaolin and release kinetics of urea from it. Journal of Applied Polymer Science106(5), 3007-3015. http://dx.doi.org/10.1002/app.26919

13 Alizadeh, T. (2010). Preparation of molecularly imprinted polymer containing selective cavities for urea molecule and its application for urea extraction. Analytica Chimica Acta669(1-2), 94-101. http://dx.doi.org/10.1016/j.aca.2010.04.044. PMid:20510909. 

14 Zhao, Y., Tan, T., & Kinoshita, T. (2010). Swelling kinetics of poly (aspartic acid)/poly (acrylic acid) semi‐interpenetrating polymer network hydrogels in urea solutions. Journal of Polymer Science. Part B, Polymer Physics48(6), 666-671. http://dx.doi.org/10.1002/polb.21936

15 Mulder, W. J., Gosselink, R. J. A., Vingerhoeds, M. H., Harmsen, P. F. H., & Eastham, D. (2011). Lignin based controlled release coatings. Industrial Crops and Products34(1), 915-920. http://dx.doi.org/10.1016/j.indcrop.2011.02.011

16 Crisp, S., Kent, B. E., Lewis, B. G., Ferner, A. J., & Wilson, A. D. (1980). Glass-ionomer cement formulations. II. The synthesis of novel polycarboxylic acids. Journal of Dental Research59(6), 1055-1063. http://dx.doi.org/10.1177/00220345800590060801. PMid:6929290. 

17 Villanova, J. C., Oréfice, R. L., & Cunha, A. S. (2010). Aplicações farmacêuticas de polímeros. Polímeros: Ciência e Tecnologia20(1), 51-64. http://dx.doi.org/10.1590/S0104-14282010005000009

18 Pinto, M. C., Gomes, F. W., Melo, C. K., Melo, P. A., Jr., Castro, M., & Pinto, J. C. (2012). Production of poly (acrylic acid) particles dispersed in organic media. Macromolecular Symposia319(1), 15-22. http://dx.doi.org/10.1002/masy.201100251

19 Kaczmarek, H., & Szalla, A. (2006). Photochemical transformation in poly (acrylic acid)/poly (ethylene oxide) complexes. Journal of Photochemistry and Photobiology A Chemistry180(1), 46-53. http://dx.doi.org/10.1016/j.jphotochem.2005.09.014

20 Jin, S., Yue, G., Feng, L., Han, Y., Yu, X., & Zhang, Z. (2011). Preparation and properties of a coated slow-release and water-retention biuret phosphoramide fertilizer with superabsorbent. Journal of Agricultural and Food Chemistry59(1), 322-327. http://dx.doi.org/10.1021/jf1032137. PMid:21155599. 

21 Wang, Y., Liu, M., Ni, B., & Xie, L. (2012). κ-Carrageenan-sodium alginate beads and superabsorbent coated nitrogen fertilizer with slow-release, water-retention, and anticompaction properties. Industrial & Engineering Chemistry Research51(3), 1413-1422. http://dx.doi.org/10.1021/ie2020526

22 Liang, R., & Liu, M. (2006). Preparation and properties of a double-coated slow-release and water-retention urea fertilizer. Journal of Agricultural and Food Chemistry54(4), 1392-1398. http://dx.doi.org/10.1021/jf052582f. PMid:16478265. 

23 Lages, F., Silva-Graça, M., & Lucas, C. (1999). Active glycerol uptake is a mechanism underlying halotolerance in yeasts: a study of 42 species. Microbiology145(9), 2577-2585. http://dx.doi.org/10.1099/00221287-145-9-2577. PMid:10517611. 

24 Arruda, P. V. D., Rodrigues, R. C. L. B., & Felipe, M. D. A. (2007). Glicerol: um subproduto com grande capacidade industrial e metabólica. Reviews in Analgesia26, 56-62. Retrieved in 2017, July 27, from http://www.revistaanalytica.com.br/ed_anteriores/26/art04.pdf 

25 Wang, S. (1974). US Patent No 3,842,022. Washington: U.S. Patent and Trademark Office. 

26 Eritsyan, M. L., Gyurdzhyan, L. A., Melkonyan, L. T., & Akopyan, G. V. (2006). Copolymers of acrylic acid with urea. Russian Journal of Applied Chemistry79(10), 1666-1668. http://dx.doi.org/10.1134/S1070427206100223

27 Spychaj, T. (1989). Low molecular weight polymers of acrylic acid and copolymers with styrene. Progress in Organic Coatings17(2), 71-88. http://dx.doi.org/10.1016/0033-0655(89)80015-9

28 Fernandes, B. S., Carlos Pinto, J., Cabral‐Albuquerque, E., & Fialho, R. L. (2015). Free‐radical polymerization of urea, acrylic acid, and glycerol in aqueous solutions. Polymer Engineering and Science55(6), 1219-1229. http://dx.doi.org/10.1002/pen.24081

29 Parikh, D., Bronck, J., & Mogavero, M. (1996). Handbook of pharmaceutical granulation technology. New York: Marcel Dekker. 

30 Kage, H., Dohzaki, M., Ogura, H., & Matsuno, Y. (1999). Powder coating efficiency of small particles and their agglomeration in circulating fluidized bed. Korean Journal of Chemical Engineering16(5), 630-634. http://dx.doi.org/10.1007/BF02708143

31 Lan, R., Liu, Y., Wang, G., Wang, T., Kan, C., & Jin, Y. (2011). Experimental modeling of polymer latex spray coating for producing controlled-release urea. Particuology9(5), 510-516. http://dx.doi.org/10.1016/j.partic.2011.01.004

32 Madhurambal, G., Mariappan, M., & Mojumdar, S. C. (2010). TG-DTA, UV and FTIR spectroscopic studies of urea–thiourea mixed crystal. Journal of Thermal Analysis and Calorimetry100(3), 853-856. http://dx.doi.org/10.1007/s10973-010-0763-3

33 Fischer, P. H. H., & McDowell, C. A. (1960). The infrared absorption spectra of urea-hydrocarbon adducts. Canadian Journal of Chemistry38(2), 187-193. http://dx.doi.org/10.1139/v60-025.

34 Krimm, S. (1955). Frequency shift of the CO stretching band in polypeptides and proteins. The Journal of Chemical Physics23(7), 1371-1372. http://dx.doi.org/10.1063/1.1742308

35 Costa, M. M., Cabral-Albuquerque, E. C., Alves, T. L., Pinto, J. C., & Fialho, R. L. (2013). Use of polyhydroxybutyrate and ethyl cellulose for coating of urea granules. Journal of Agricultural and Food Chemistry61(42), 9984-9991. http://dx.doi.org/10.1021/jf401185y

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