Use of Polyhydroxybutyrate and Ethyl Cellulose for Coating of Urea Granules

Abstract

Fertilizers contain essential nutrients for agricultural growth and development. However, most nitrogen fertilizers are substances with high solubility of ions and are very susceptible to leaching and volatilization. To minimize these losses, an alternative is the creation of a physical barrier around granules. One way is to coat granules with polymers. In the present work urea granules were coated with polyhydroxybutyrate and ethyl cellulose in various conditions in the presence of emulsifiers. The original granules and the final products were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetry, to evaluate the surface morphology, the interaction between the granules and the coating, and the rates of mass change. The rates of urea release in distilled water were measured with a commercial enzyme kit. It is shown that those polymers are effective for coating of granules, leading to reduction of rates of urea dissolution in water.

Encapsulated Urea-Kaolinite Nanocomposite for Controlled Release Fertilizer Formulations

“…The first weight loss was observed at approximately 100-125 ∘ C corresponding to the following: (i) the loss of nonconstitutional water, (ii) removal of interlayer water, (iii) elimination of water coordinated to exchangeable cations or structural water as mentioned in [63], and (iv) degradation of urea; this discloses the fact that the release properties of our engineered urea CRF formulation would work best at that temperature range. Based on the findings obtained by [64], urea loss at about 140-250 ∘ C is caused by both (i) its own vaporization and (ii) degradation to its complementary form known as biuret [NH(CO) 2 (NH 2 ) 2 ]. The second weight loss was observed at about 225-350 ∘ C attributed to (i) the continuous sublimation of urea and (ii) decomposition or self-condensation of biuret [NH(CO) 2 (NH 2 ) 2 ] to more complex decomposition product to the completion of vaporization and degradation reaction [64].…”

“…Based on the findings obtained by [64], urea loss at about 140-250 ∘ C is caused by both (i) its own vaporization and (ii) degradation to its complementary form known as biuret [NH(CO) 2 (NH 2 ) 2 ]. The second weight loss was observed at about 225-350 ∘ C attributed to (i) the continuous sublimation of urea and (ii) decomposition or self-condensation of biuret [NH(CO) 2 (NH 2 ) 2 ] to more complex decomposition product to the completion of vaporization and degradation reaction [64]. The third weight loss was observed at around 500-575 ∘ C and was ascribed to the dehydroxylation of kaolinite a phenomena constituted by the decomposition of urea-kaolinite intercalated compound as well as elimination of structural hydroxyl and organic matter [45,62,63].…”

Dynamics of Kaolinite-Urea Nanocomposites via Coupled DMSO-Hydroxyaluminum Oligomeric Intermediates

“…The second and third degradation phases around 75-230 ∘ C and 250-320 ∘ C correspond to both urea vaporization and its complementary degradation compound biuret [NH(CO) 2 (NH2) 2 ], respectively. Preliminary kaolinite dehydroxylation as well as continuous sublimation of urea to its complex decomposition product corresponds to fourth and fifth degradation phases seen at 350-550 ∘ C and 550-800 ∘ C [63], respectively.…”

Polymers and its applications in agriculture

“…Urea Chitosan [25][26][27] Polyhydroxybutyrate (phb), ethyl cellulose Polyethylene, polyvinyl acetate, polyurethane, polyacrylic, polylatic acid KH 2 PO 4 Chitosan, gellan gum [28] NPK Chitosan [29][30][31] Cellulose, natural gum, rosin, waxes…”