STP1449

    Dynamic Investigations of the Formation of Phenoxy Ester Herbicide Concentrated Emulsions

    Published: Jan 2003


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    Abstract

    Dynamic interfacial tension (DIT) measurements have been employed to investigate the formation dynamics of iso-octyl 2,4-dichlorophenoxyacetate (2,4-D IOE) concentrated emulsion (EW) by citric acid alkylether ester (AEC) emulsifiers. Both of the AEC surfactants, AEC-1 and AEC-3, were found to be quite effective in reducing the interfacial tension between water and 2,4-D IOE when compared with a standard nonionic surfactant. The CMC concentrations and effective molecular areas of AEC-1 and AEC-3 have been determined at both air/water and 2,4-D IOE /water interfaces. Kinetic analysis indicated that the adsorption of AEC-1 proceeded at a faster rate than that of AEC-3 at 2,4-D IOE/water interface. But, AEC-3 is more effective in minimizing the equilibrium interfacial tension at the 2,4-D IOE /water interface. The DIT results have been contrasted with those obtained with Focused Beam Reflectance Measurement (FBRM). The results are further correlated to the rate at which 2,4-D IOE EW reaches its equilibrium particle size and longer-term physical stability. The robust physical stability exhibited by the 2,4-D IOE EW formulated with AEC-3 is attributed to the minimal interfacial tension of the system.

    Keywords:

    Dynamic interfacial tension (DIT), 2,4-D IOE, surfactant, alkyl ether citrate, emulsifier, emulsion, FBRM, focused beam reflectance measurements, suspension, concentrated emulsion, weed control, particle size, agricultural


    Author Information:

    Lei, Y
    Scientist, Chemist, and R&D Manager, Akzo Nobel Surfactant America, Dublin, OH

    Alexander, M
    Scientist, Chemist, and R&D Manager, Akzo Nobel Surfactant America, Dublin, OH

    Hazen, JL
    Scientist, Chemist, and R&D Manager, Akzo Nobel Surfactant America, Dublin, OH


    Paper ID: STP11201S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP11201S


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