Study Of The Microencapsulaton Technology Of DEET

DEET is a sort of effective, broad-spectrum insect repellent, which was invented over 50 years.DEET is still used extensively against both human and animal pests. DEET has many advantages, such as broad-spectrum and low toxicity, but the longevity of DEET action is short and the quantity of DEET absorption through the skin is much, which potentially could increase the risk of dermatitis or DEET-induced toxicity. Microencapsulation technique can prolong the action longevity of DEET and reduce quantity of DEET absorption through the skin, with no influence on it effect.This paper studies the microencapsulation of DEET by complex coacervation.The main content of this study is the influence of several operational parameters of complex coacervation, and investigation control release performance of microcapsules.Several operational parameters, such as the composition ratio between coating material and core material, the preparation temperature, the preparation time, the mixer rotation speed, the HLB value of emulsion and the content of emulsion, are investigated in the single factor analysis. Furthermore, the optimum condition of complex coacervation is achieved by orthogonal experiment, including the composition ratio between coating material and core materiall is 1:1, the preparation temperature is 40℃, the preparation time is 40min, the mixer rotation speed is 2000r/min, the HLB value of emulsion is 12 and the content of emulsion is l%.The microencapsulation efficiency reaches 75.3%.Finally, the microencapsulation product has been characterized, the control release performance of the microcapsule shows that the average control release velocity is 12.44μg/cm~2·h in 24 hours,much less than the normal evaporation velocity of DEET 22.6±2.183μg/cm~2·h.This study also compares the influence of metamorphic reagent formaldehyde,the results show that the content of metamorphic reagent formaldehyde affects control release velocity, the control release of microcapsules can be controlled by formaldehyde dosage.The results show that it is feasible to prolong the action time and reduce quantity of DEET absorption by complex coacervation. The process of complex coacervation is simple; material is cheap.It shows a great prospect in the industrial application.