Preparation, characterization and biological activity evaluation of pirimiphos-methyl microcapsules

In this study, polyurethane microcapsules loaded with pirimiphos-methyl were prepared by an interfacial polymerization method using modified poly-isocyanate as the precursor and triethanolamine as a curing agent. The microcapsules were fully characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and so on. The results showed that the microcapsules had good morphology, excellent encapsulation efficiency (90.88%) and loading ability (about 50%) for pirimiphos-methyl. Furthermore, the microcapsules exhibited an excellent sustained release property (above 8 days) in 50% isopropanol aqueous solution(v/v). The biological activity on Musca domestica showed that the microcapsules persistence period was above 90 days, which was longer than emulsifiable concentrate formulation.