Preparation And Controlled Release Property Of The Reused Polystyrene-Coated Urea

In this paper, the preparation of coated fertilizers with the reused polystyrene and its controlled release property were studied. Two solvent serials (A and B) were investigated, including ethyl acetate, dibutyl phthalate and oil for serial A and ethyl acetate, methylbenzene and surfactant (T1, T2, T3) for serial B were investigated. The results showed that the best concentration of dibutyl phthalate and oil for serial A were 3% and 2%. For serial B the ratio of ethyl acetate to methylbenzene was 1:1 and 4% surfactant T3 was better than the others (T1 and T2) for the formation of polystyrene films.The controlled release property of coated fertilizers was investigated by the methods of water dissolving and soil leaching experiments. The results showed that the coated fertilizers had a signification controlled release property. The preliminary solubility percentages of the coated fertilizers were below 40% except for A-6, A-7 and B-6. The preliminary solubility percentage of serial B fertilizers was less than that of serial A. Then six coated fertilizers with good preliminary solubility percentage were carried out the soil leaching experiment. The experiments demonstrated that the coated fertilizer had good controlled release property for nutrient and the states of the film wrapping the fertilizers were good by scanning electron micrograph. The weight coated had an important influence on the controlled property of coated fertilizers and its best proportion was 10% for serial A and B fertilizers. So the reused property can be used as the coated material of fertilizer.