Microencapsulation of pendimethalin with polyurethane-urea and determination of its stability

Abstract

In this study, pendimethalin (PM) used as an herbicide was encapsulated using interfacial polymerization method. The size, shell thickness, microencapsulation efficiency, the effect of mixing speed on capsule size and active substance release times of the produced microcapsules were investigated. Polyurethane-urea resin, which is the main component of the capsule shell, was synthesized using isocyanate / glycol / amine at different molar ratio at 55°C for 180 min. It was measured that the microencapsulation efficiency was 53.2–89.1% and the microcapsule shell thickness was 399.7–1479.0 nm. The lowest and highest release percentages of microcapsules under alcohol-water and ultraviolet (UV) light for 4 h at 20°C were found to be 30.79% and 40.12%, respectively. It has been found that the microcapsules containing ethyl glycol in the capsule wall composition had the highest stability, and the capsules containing PEG-400 in the capsule wall structure had the highest capsulation efficiency.

Keywords

• microencapsulation
• pendimethalin
• polyurethane-urea