Coating of Urea Granules for Slow Release Fertilizer Using Bioblend Polystyrene / Polycaprolactone

The usage of bioblend polystyrene/polycaprolactone for coating of urea as a slow release fertilizer dosage form has been carried out. Bioblend was prepared by mixing polystyrene with polycaprolactone. The purposes of addition of polycaprolactone biopolymers on polystyrene, not only to obtain the biodegradable sealant characteristic, but also expected to create pores. Bioblend polystyrene/polycaprolactone has good compatibility with the urea granules and higher efficiency of the polymer coating on the urea, could reduce the release rate of nutrients from fertilizers. Results showed that the release rate of fertilizer products obtained were slower than the uncoated urea granules. The release of the active substance from coated urea on the soil media in formula 2 and 3 after 10 days of testing were only 18.3, and 28.0% w/w, respectively. The release profile of urea using the mud media was slower than in distilled water and soil media as well. Meanwhile, the total released of the fertilizer in aqueous media from all of formulas were average of 24 hours. It shown improper applications using the aqueous media. The percentage of urea released after 10 days of testing using mud media from formula 2 and 3 were only 7.9, and 9.5% w/w, respectively. Formulas of bioblend polystyrene/polycaprolactone coated urea obtained were suitable and fulfill as a slow release fertilizer product.