Research Of Microencapsulation Of Grass Herbicides Isoamyl Ketone

Clomazone is a selective herbicide with high efficiency.In this paper, herbicides Clomazone Microencapsulation a systematic study, by changing the type and amount of emulsifier, emulsification of the way, the rate of mixing, emulsification reaction time and other factors, study their effect on the emulsion; In the pre-polymerization stage, the influence of the effect of pre-polymerization reaction medium p H, reaction temperature and reaction time were studied; examined the skin-core ratio, catalyst type, reaction time and reaction temperature, acidification is affecting factors on the polycondensation Reaction Effect; the same time, micro-encapsulation process of the microscope, scanning electron microscopy and infrared spectroscopy characterization of the microcapsules and the distribution of particle size and release properties of microcapsules and the embedding rate studied. Study results are as follows:1.Tween-80, OP-10 and Span-80 emulsifier, OP-10 is better emulsification, microcapsules particle size distribution is more concentrated; OP-10 the amount from 0.1% to 0.4%, Clomazone emulsifying effect of microcapsules are relatively homogeneous, emulsion droplets are moderate, while the amount of foam produced different.2.shaking, stirring, microwave and emulsion injection method, mixing the emulsion emulsified better way, uniform emulsion, emulsion droplets moderate size concentration; with the stirring speed increases, the emulsion droplets decreases, and gradually spread becomes uniform, when the stirring speed of 7 000r/min best emulsifying effect; emulsifying time is too short, emulsification less effective; emulsion too long, the micro-capsule size is too small, while reducing the synthesis of microcapsules work efficiency, increase operating costs, emulsification time of 10 min, the emulsion uniformity, particle size is moderate, the effect is better.3. the pre-polymerization stage, the reaction medium p H of acidic or alkaline, the prepolymer results are not good, the reaction medium p H is neutral to slightly alkaline(p H = 7.5) effect optimal solution to transparent viscous state, the amount of microcapsules more; low temperature and high temperature pre-embedding poor polymerization, the reaction temperature at 55 ℃, the prepolymer clear and transparent, in the acid-catalyzed condensation, a higher rate of micro-capsule embedded, to good effect;prepolymer reaction in catalytic conditions than 40 min, 50 min above, it will produce a white cloudy precipitate, coating rate, pre-polymerization time of 45 min or so, obtain a transparent water-soluble prepolymer, can be completely dissolved in the core material as the dispersed phase, water as the continuous phase dispersion in situ polymerization.4.core skin than too large, there has not been coated core material, embedding is not complete, but the release is very good; with ammonium chloride, formic acid, citric acid as a catalyst, the condensation reaction at p H 1.5 ~ 2.0、2.5、3.0, including better use of ammonium chloride, microcapsule structure close to spherical; acidification time should not be too short and too long, 3h, and so obtain a smaller particle size distribution of micro-capsules.5.the polycondensation reaction temperature is less than 55 ℃, the small size of the microcapsules, but uneven; polycondensation reaction temperature is higher than 65 ℃, a larger particle size of microcapsules, a concentration phenomenon; polycondensation reaction temperature is 55 ℃ When finished microcapsules coated compact, small and uniform particle size and better dispersion.6.micro-capsules for the uniform distribution of spherical particles and the average diameter of about 0.2μm, with a good slow release.7.IR characterization showed that the formation of the trimer formation of resin wall, urea- melamine- formaldehyde resin with a high degree of cross-linked, and there is no cross-linked chain ether bond, forming a capsule core coated microcapsules.