Abstract: By adopting the interfacial polymerization method, anti-mosquito microcapsules using polyurea as wall material and containing Propoxur were prepared. This paper discusses the influence of composite emulsifier, core-wall ratio, reaction time, reaction temperature and stirring speed on the particle size and distribution of microcapsule, encapsulation efficiency, hydrolysis rate and structure. Results show that main factors that influence microcapsule preparation are core-wall ratio and reaction time, and the secondary factors are reaction temperature and stirring speed. The optimized condition of the microcapsules preparation is as follows: preparing the emulsifier by using Tween80 and Span80 at 1∶1 ratio, the core-wall ratio is 1∶2.5, reaction time is 3.5 hours, reaction temperature is 60 ℃ and stirring speed is 550 r/min. The microcapsules prepared under this condition have 75.8% of encapsulation efficiency, 20.7% of hydrolysis rate, and 2.341 μm of average particle size with a uniform distribution.FTIR analysis and SEM observation verify that spherical microcapsules have been successfully prepared.And the biological test proves that this kind of microcapsule has long-lasting anti-mosquito property.

Key words: interfacial polymerization; Propoxur; polyurea microcapsule; anti-mosquito properties;controlled-release