Original Articles: 2013 Vol: 5 Issue: 5
Preparation of chlorpyrifos microcapsules by interfacial polymerization
Chlorpyrifos microcapsules were prepared by interfacial polymerization, with toluene-2,4- diisocyanate and hexamethylenetetramine as wall material, and poly(vinyl alcohol) as dispersant. Optimal emulsification shear rate, shear time and interfacial polymerization stirring speed and interfacial polymerization time were determined by pre-experiment. Optimal ratio of raw materials for preparation of chlorpyrifos microcapsules was obtained by experiments. The chlorpyrifos microcapsules prepared were characterized by UV spectrophotometer and laser particle size distribution analyzer. The optimum mount of raw materials are that chlorpyrifos is 1.0g, toluene-2,4-diisocyanate is 0.3g, hexamethylenetetramine is 0.7g and poly(vinyl alcohol) is 1.0g. The optimal operating conditions are that interfacial polymerization stirring speed is 500r/min and interfacial polymerization time is 40 minutes. In above-mentioned conditions, mean particle size of chlorpyrifos microcapsules prepared is 0.89ÃŽÂ¼m, and encapsulation efficiency can reach 92.98%.