Controlled-Release Material for Urea Fertilizer from Polylactic Acid
Urea fertilizer is a major source of nitrogen, which is one of the essential nutrients for plant growth. Due to its uncontrollable release, this chemical can be wasted easily by leaching and volatilization that can adversely cause the contamination to the environment. In this work, a controlled-release material for urea fertilizer has been prepared by using degradable polylactic acid. Unlike other conventional controlled-release system, the resulting material is able to provide an efficient supply of urea fertilizer, without causing further contamination to the environment from residue material, as polylactic acid can be degraded in the environment. Micron-size particles of polylactic acid coated urea were prepared by employing atomizing technique. Effect of the preparation conditions; urea/PLA composition, PLA concentration, and pressure of atomizing gun on the particle size of material are investigated. The urea release rate of these samples is then studied by employing UV-Visible spectrophotometer. In addition, the effect of preparation conditions on shape and morphology of sample is determined by using Scanning Electron Microscope (SEM).
J. Papangkorn et al., "Controlled-Release Material for Urea Fertilizer from Polylactic Acid ", Advanced Materials Research, Vols. 55-57, pp. 897-900, 2008