Preparation and Sustained-release Behavior of Abamectin Urea-formaldehyde Resin Microcapsules

Microcapsules containing abamectin were synthesized via the in-situ polymerization method using urea-formaldehyde(UF) as a wall material.The particles size range and the surface morphology of the microcapsule were analyzed with varying formaldehyde/urea (F/U) mole ratio,solvent and dispersant.The sustained-release characteristics of abamectin CS was also studied.The optimal conditions were as follows:The F/U mole ratio was 1.75,toluene and chlorobenzene at weight ratio of 3∶ 4,the dosage of dispersant NNO was 1.5％ ,the dosage of silicone defoamer X-10C was 0.7％.The microcapsules showed satisfied surface morphology and particle size distribution,with the mean particle diameter of 4.07 μm.The product displayed good stability and its encapsulation ratios were 98.89％.IR spectra showed that abamectin was contained in urea-formaldehyde wall.The profile could be described by the first order kinetics equation,the release t50 of AVM CS was about 3.4 times as much as AVM TC,AVM CS has obviously sustained effect.