Organic silicone-modified transgenic soybean oil as bio-based coating material for controlled-release urea fertilizers

Novel bio-based polyurethanes (PUs) were synthesized from transgenic soybean oil (TSBO) and then modified with hydroxyl-terminated dimethyl silicone (HTMS) to coat urea prills for controlling nitrogen (N) release. Different kinds of coated ureas were prepared from these hydrophobic PUs. Physicochemical properties of the coatings were characterized in the laboratory. The N release characteristics of the PU-coated ureas (PCUs) in water were determined at 25 degrees C. Experimental results showed that the presence of HTMS in the PUs reduced the coating porosity, increased the water-contact angle of the coating material, and thus slowed the nutrient release from the PCUs. These results suggested that HTMS improved the structure and properties of coating materials for controlled release. These findings showed that bio-based PUs derived from TSBOs made excellent coating material, particularly after HTMS modification, and thus may replace petroleum-based PUs for controlled-release fertilizers. (C) 2016 Wiley Periodicals, Inc.