Study on pre-polymerization condition of clomazone herbicide microcapsules by in-situ polymerization

Microcapsules with a urea-formaldehyde resin wall were prepared for clomazone herbicide by in-situ polymerization method.The influences of pre-polymerization conditions of urea-formaldehyde,such as molar ratio of urea-formaldehyde,pH value of reaction medium,reaction temperature and reaction time,on the formation of Clomazone herbicide microcapsules,the structure,the size and distribution of particle size and the microcapsulated ratio of core material to the microcapsules were discussed.The results show that molar ratio of urea-formaldehyde n(urea)∶n(formaldehyde)=1︰2.0,pH value is 8.0,reaction temperature is 70 ℃,reaction time is 60 min,the water-solubility of the urea-formaldehyde is good and when it is used in preparation of microcapsule,the microcapsules of fluidizable solid particles with close surface structure wall are prepared.The distribution of particle size is uniform and the ratio of core material to MC is 26.7%.