Nonionic Surfactants as Associative Thickeners in Aqueous Flowable Pesticide Formulations

Mente, Donald C.

doi:10.1520/stp19394s

Cited by 4 publications

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Effect of Atrazine Contamination on Compressibility and Permeability Characteristics of Clay

Keramatikerman

Chegenizadeh

2017

Geotechnical Testing Journal

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Atrazine (ATZ) is one of the most heavily used herbicides in the world, particularly in the United States and Australia. This study evaluated the compressibility and permeability characteristics of two Western Australia natural clays contaminated with varying ATZ contents. A series of one-dimensional consolidation tests using fixed-ring oedometer device were conducted, and the final hydraulic conductivity was calculated at the end of each loading stage. At the first stage, the strain–time graphs at 1,280 kPa effective overburden pressure (σ′n) were evaluated, and the results indicated that the specimens with a greater ATZ content have higher values of final vertical strain (ϵv). Then, the compression index (Cc) values were computed from the void ratio–effective overburden pressure curves (e−σ′n), and the results showed that the compression index (Cc) increased as the ATZ content of the tested clays increased. At the next stage, the coefficient of consolidation (cv) was calculated using the Casagrande method and the Taylor method. The results showed that the computed coefficient of consolidation (cv) using the Taylor method was slightly greater than those calculated using the Casagrande method in both tested clays. Also, the hydraulic conductivity (k) values of the tested clays increased as the contamination content increased (i.e., 3.1 × 10-7 ≤ k ≤ 129 × 10-7 cm/s and 4.49 × 10-9 ≤ k ≤ 95.3 × 10-9 cm/s). This behavior, which was attributed to promotion of the agglomeration and aggregation between clay particles, promoted formation of the tiny voids in the soil. Finally, the secondary compression ratio (Rα) and secondary compression index (Cα) were computed, and the results showed that the specimens containing higher ATZ content had greater values of Rα and Cα.

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Effect of Atrazine Contamination on Compressibility and Permeability Characteristics of Clay

Keramatikerman

Chegenizadeh

2017

Geotechnical Testing Journal

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Effect of Temperature Fluctuations and Storage Period on Pesticide Stability in Formulation Concentrates Used in Forestry

Sundaram

1995

Pesticide Formulations and Application Systems: Fourteenth Volume

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Pesticide formulation concentrates should maintain their physicochemical stability from the time of preparation until field application. Literature information on pesticide stability is lacking at present, especially after field storage under the conditions of the operational spray programs for forest pest control. The present study provides information on the influence of water hardness, pH, formulation ingredients, carrier media, storage periods, and temperature fluctuations, on phase separation, pesticide hydrolysis, degradation and metabolism, in some simple formulation concentrates prepared in the laboratory, and in some complex formulation concentrates obtained from pesticide companies. The investigation indicated that the greater the hardness of water, the greater the stability of the active ingredients. Formulants increased the storage stability of pesticides. Polymeric formulants of larger molecular mass provided greater stability to pesticides than the surfactants of smaller molecular size. The longer the storage period, the lesser the stability of pesticides. Highly water-soluble pesticides degraded to a much greater extent than the sparingly soluble ones. Degradation occurred much more in aqueous media than in non-aqueous media, and the type of metabolites formed differed in the two media. Commercial formulation concentrates made up of several ingredients provided metabolites different from those found in the simple formulations prepared in the laboratory. Pesticide degradation occurred to a much greater extent after storage of the commercial formulation concentrates under outdoor conditions at extreme fluctuating temperatures, than after storage in the laboratory at a constant temperature.

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Methyl Vinyl Ether Maleic Acid Half Ester Copolymers as Dispersing Agents in Aqueous Flowable Formulations

Curry

Goehner

Narayanan

1998

Pesticide Formulations and Application Systems: Eighteenth Volume

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Aqueous-based flowables have been studied using methyl vinyl ether monoalkyl maleate copolymers as anionic dispersing agents for pesticides such as atrazine, carbaryl, and chlorothalonil. These polymers have received EPA exemption for use in crop protection and on animals. The polymer types, which differ in the length of the alkyl ester side chain, or contain a carboxylic acid instead of the monoester with appropriate neutralization, were each paired with either nonionic or anionic surfactants, such as nonylphenol ethoxylate, tristyryl phenol ethoxylate, or N-methyl taurate, in water-based suspension concentrates. Physical-chemical data show these anionic polymers, new for agricultural applications, can be used to make stable dispersions with different pesticides under varying conditions of hard water. Prototype formulations and comparative stability data with commercial formulations are provided. A working model is used to explain the role of the polymers in stabilizing dispersions.

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Nonionic Surfactants as Associative Thickeners in Aqueous Flowable Pesticide Formulations

Cited by 4 publications

References 0 publications

Effect of Atrazine Contamination on Compressibility and Permeability Characteristics of Clay

Effect of Atrazine Contamination on Compressibility and Permeability Characteristics of Clay

Effect of Temperature Fluctuations and Storage Period on Pesticide Stability in Formulation Concentrates Used in Forestry

Methyl Vinyl Ether Maleic Acid Half Ester Copolymers as Dispersing Agents in Aqueous Flowable Formulations

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