Paper Title
Scale-Up the Production Capacity of Slow Release Urea with Polystyrene – Starch Mixed Coating and its Characterization

Slow-release fertilizers are useful in increasing the efficiency of nutrient utilization by plants and reducing side effects due to the use of conventional fertilizers. This study aims to increase the production capacity of slow-release urea from the mixed of starch polystyrene coating formula (2:1) which was the best formula in previous study to 10, 20, 40, and 80 times. In this study, measurements of coating efficiency, granule size distribution, granule morphology, and coating thickness measurements were carried out using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), and release tests on distilled water, soil, and mud media. The results of the measurement of coating efficiency on formulas 1, 2, 3, and 4 were 82, 80.9, 88.7, and 89.6%. The coated urea has a granule size in the diameter range of 1.5 to 3.6 mm. On the observation of the surface morphology of the coating looks smooth, compact, and uniform. Results of coating thickness measurements on formulations 1, 2, 3, and 4 were 49.22, 20.34, 30.33, and 39.05 μm. The FTIR result of slow-release urea showed the same spectrum as uncoated urea. The DSC test of coated urea showed a melting point of 136.53°C and the melting point of starch polystyrene polymer did not show a melting point. The release test on distilled water, soil and mud media in this study still showed a slow release of urea when compared to conventional urea. It can be concluded that the increase in the capacity of slow-release urea with starch-polystyrene mixed coating did not affect the characteristics and release of urea compared to previous studies. Keywords - Scale-Up, Fertilizer, Slow Release, Polystyrene, Starch, Urea