Original Articles
Elfi Sahlan Ben, Muslim Suardi
Abstract
Urea is a most widely used fertilizer in agriculture due to high nitrogen content, low cost, and commercial availability, but there are some finites related with in-effective used of the fertilizer, and environmental pollution. This study aim was to produce urea slow-release microcapsules using polycaprolactone as coating material by solvent evaporation method. The ratio of urea-PCL were 1:1, 1:2, and 1:3. Microcapsules obtained were characterized by Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy (SEM), particle size distribution, amount of urea entrapped in microcapsules, and release kinetics profile. There was no chemical interaction between urea and polycaprolactone. The result of SEM showed that microcapsules were spheric in shape with the rough surface and aggregate formed. Particle size distribution of coated urea microcapsules was in the range of 20-240 μm, influenced by the concentration of PCL. Encapsulation efficiency of urea microcapsules in formula 1, 2, and 3 were 80.28 ± 0.81, 82.65 ± 1.22, and 79.64 ± 0.65%, respectively. The percentage of release efficiency from formula 1, 2, and 3 were 58.85 ± 1.72, 26.76 ± 0.76, and 40.42 ± 2.39%, respectively. In conclusion, PCL could be used in microencapsulation formulation of urea slow release. The release kinetics of urea from microcapsules followed Langenbucher equation related with diffusion and erosion mechanism. PCl affected the release efficiency significantly (p<0.05).