Role of Urea and Melamine as synergic co-plasticizers for starch composites for fertilizer application

Authors: GIROTO, AMANDA - Embrapa; GARCIA, RODRIGO - Embrapa; COLNAGO, LUIZ - Embrapa; Klamczynski, Artur; Glenn, Gregory - Greg; RIBEIRO, CAUE - Embrapa

Submitted to: International Journal of Biological Macromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2019
Publication Date: 12/13/2019
Citation: Giroto, A., Garcia, R.H., Colnago, L.A., Klamczynski, A.P., Glenn, G.M., Ribeiro, C. 2019. Role of Urea and Melamine as synergic co-plasticizers for starch composites for fertilizer application. International Journal of Biological Macromolecules. 144:143-150. https://doi.org/10.1016/j.ijbiomac.2019.12.094.
DOI: https://doi.org/10.1016/j.ijbiomac.2019.12.094

Interpretive Summary: Much of the nitrogen from fertilizers is lost each year to runoff, leaching out of the root zone, volitization, or other factors. ARS scientists in Albany, Ca in collaboration with scientists from the Brazilian agricultural organization (EMBRAPA) developed a controlled-release nitrogen fertilizer containing urea and melamine as nitrogen sources. Starch was used in an extrusion process to encapsulate the fertilizer and provide a controlled-release mechanism that gradually metered out the nitrogen over time. This research could result in more efficient fertilizers with minimal losses of nitrogen in the environment.

Technical Abstract: Herein we describe the interaction of starch, urea, and melamine (C3N6H6) in composite materials for use as controlled-release plant fertilizer. Slow-release fertilizers are important in minimizing nutrient losses due to run-off, leaching, and other factors. Urea is an effective plasticizer for starch and is an important nitrogen fertilizer throughout the world. Melamine also has high nitrogen content and could be combined with urea-starch composites to provide enhanced controlled-release fertilizer. This study reports the structural interaction and the performance gain of melamine addition to starch-urea composites. Composites were characterized by spectroscopic techniques (FT-Raman and 13C-NMR). The results showed that melamine modifies the crystallinity of native starch thereby increasing the plasticization of starch compared to composites with only urea. The data indicate that melamine modifies the crystallinity of native starch, suggesting an enhanced starch plasticizing effect of starch-urea composites. Further research into the co-plasticization of starch by urea and melamine could be exploited for improved controlled-release fertilizer products.