| Polycarboxylate dispersants have unique dispersion properties,which can affect the stability of pesticide formulations.In this paper,we applied different polycarboxylate dispersants to prepare three different suspension concentrates,namely 350 g/L Imidacloprid,18% atrazine + 18% glufosinate and 250 g/L azoxystrobin.These pesticides' targets are different,they are used as insecticides,herbicides and fungi-cides respectively.The storage stability of three kinds of pesticide aqueous suspensions was studied.The results showed that the suspension rate,particle size,Zeta potential and viscosity of three kinds of systems before and after heat storage were all met the requirements of long-term stability of pesticide suspension under the storage condition of 54±2? for 14 days.Three kinds of pesticide suspension concentrate with shear thinning flow properties are in accordance with Herschel-Bulkley rheological model,and their yield values are in the range required for stable storage of pesticide aqueous suspension systems.Thus,three pesticide aqueous suspensions prepared from polycarboxylate dispersants have long-term storage stability.The adsorption characteristics and absorption thermodynamics of polycarboxylate dispersants onto azoxystrobin particle surfaces were studied.The adsorption experiment data fit the Langmuir monolayer adsorption model well.The thermodynamic parameters are as follows: ?Gad<0,?Sad>0,?Had<0 and |?Had|<40 kJ·mol-1,which indicat that the adsorption is a spontaneous exothermic physical process.The effect of polycarboxylate dispersant on Zeta-potential and rheological property of suspension concentrates were investigated.Results show that polycarboxylate dispersants of suitable concentration can increase the mutual repulsion between the disperse particles and improve the flow property of system by improving the Zeta potential of the suspension system,thus enhancing the long-term storage stability of the suspension concentrates. |
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