Preparation of trifluralin microspheres and its controlled release performance

In order to delay the degradation and increase the pesticides lasting validity period, silica-coated trifluralin microspheres was prepared by the emulsion method. In the preparation procedure of silica microspheres, tetraethyl orthosilicate (TEOS) was employed as the silica source and tween-60 was used as the surfactant. The factors related to the loading efficiency and controlled release behavior of free silica-coated trifluralin microspheres were investigated. Multi-level release models of temperature and pH value on the controlled-release performance were established. Silica-coated trifluralin microspheres shows regular spherical, low particle size and high loading efficiecy (50%). The stability of trifluralin increased when coated in microspheres, and release rate of trifluralin increased with the increase of pH and temperature. The trifluralin microspheres has improve the stability of trifluralin in the environment and extended its efficacy period. This study can also be used as a reference for the preparation of other pesticide microspheres.