The effect of spray thickening anti-drift adjuvants on flow rates through nozzles

Richardson, B.; Ray, John W.

doi:10.30843/nzpp.1991.44.10858

Cited by 3 publications

(6 citation statements)

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“…Adjuvants are commonly used to modify formulations by lowering surface tensions, but they also modify other physical and chemical properties. Using agrichemical sprays as an example, adjuvants change almost every aspect of the spray process from the spray spectrum coming out of the nozzle [37][38][39] to surface adhesion 33,34 to spreading 26,40 to retention 36,41,42 and uptake. 18,43,44 Much of this is put down to ST effects.…”

Section: Modelling Adjuvant Formulation Wettingmentioning

confidence: 99%

Importance of leaf surface and formulation properties in predicting wetting outcomes

Nairn

Forster

2022

Pest Management Science

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BACKGROUNDLeaf wettability is a major hurdle for the retention of agrichemical sprays that is combated, in part, by using adjuvant modified formulations. Scientists must understand the properties of the leaf surface and the formulation that govern wetting to intelligently select or formulate products to target specific pests.RESULTSA comprehensive database comprising 11 synthetic surfaces and 54 leaf surfaces (species, adaxial and abaxial sides, cultivars, and plant age) using 35 formulations (neat solutions and adjuvants solutions at different concentrations) was compiled. Surface properties of the physical roughness and chemical polarity, as quantified by the wetting tension dielectric method, and formulation properties of surface tension and polarity, as quantified by dielectric constant, were found to govern wetting. A comprehensive wetting model was developed that employed these variables and was capable of accurately predicting the wetting outcome (R2 = 0.86) on all the leaf and synthetic surfaces investigated. This model adequately predicts adjuvant formulation wetting despite exact formulation polarity being unknown.CONCLUSIONSWetting can be modelled for a wide range of surfaces and solutions. The comprehensive wetting model developed shows potential to better predict the wetting outcome of adjuvant formulations should a method to quantify the formulation dielectric constant be developed. This research provides a significant advancement in the understanding of the properties governing wetting, which may aid the selection and development of adjuvants to target specific surfaces. © 2022 Society of Chemical Industry.

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Section: Modelling Adjuvant Formulation Wettingmentioning

confidence: 99%

Importance of leaf surface and formulation properties in predicting wetting outcomes

Nairn

Forster

2022

Pest Management Science

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“…3.5 Using the estimated adjuvant IDP to model wetting Nairn and Forster 24 demonstrated that the comprehensive wetting model [eqn (2)] performs adequately if the DC of the formulation was assumed to be that of the highly polar carrier liquid water (DC = 80, R 2 = 0.76). 24 However, they acknowledge that the actual formulation polarity was likely to have been significantly lower.…”

Section: Adjuvant Idp Versus the Hlbmentioning

confidence: 99%

“…To improve, or modify, these wetting outcomes adjuvants are used to alter formulation properties. Adjuvants affect almost every aspect of the spray process from the spray spectrum coming out of the nozzle [1][2][3] to surface adhesion 4,5 to spreading 6,7 to retention [8][9][10] and uptake. [11][12][13] Much of this is put down to surface tension effects, but other formulation properties should not be discounted.…”

Section: Introductionmentioning

confidence: 99%

“…The WTD method has been shown to accurately quantify leaf surface roughness, as it pertains to leaf wettability, 28,31 and leaf surface polarity, as it pertains to spreading of pure solutions 32 and surfactant formulations. 7 A comprehensive wetting model has been developed, using the WTD measures of surface roughness and surface polarity, together with the formulation parameters ST and DC, to accurately predict wetting outcomes of a variety of solutions over an array of synthetic and leaf surfaces [Eqn (2)]. 24 This model was accurate over a wide range of conditions (R 2 = 0.86), using 12 solutions on 11 synthetic surfaces and 54 different leaf surfaces.…”

Section: Introductionmentioning

confidence: 99%

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Importance of adjuvant formulation properties in predicting wetting on leaf surfaces

Nairn

Forster

2022

Pest Management Science

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BACKGROUNDLeaf wettability can be a barrier to retention of agrichemical sprays. Adjuvants are used to modify leaf wetting by sprays to enhance retention. A previous study developed a model that accurately predicted nonadjuvant formulation wetting (contact angle) on both synthetic and leaf surfaces. Model inputs were the surface properties, roughness and polarity, as measured by the wetting tension dielectric method, coupled with the formulation properties, surface tension and dielectric constant. Preliminary work has indicated that the wetting ability of adjuvant formulations on different surfaces could be modelled in a similar way if the effect of adjuvants on solution polarity could be accurately quantified.RESULTSThe wetting of nine agrichemical adjuvants, at a range of concentrations, were measured on seven synthetic and 14 leaf surfaces. A novel method was developed to quantify the interfacial dielectric polarity (IDP) of adjuvant formulations. Adjuvant concentration did not change the IDP indicating the surface‐active surfactant molecules migrate to the interface, loading until saturation. Formulation properties of surface tension and IDP were found to be strong predictors of wetting in conjunction with surface properties of the substrate. The previously developed unaltered comprehensive wetting model could predict the wetting of adjuvant formulations on synthetic and leaf surfaces (R2 = 0.9) using these inputs.CONCLUSIONSWetting of adjuvant formulations can be modelled for a wide range of surfaces and this model is expected to advance the selection, and development, of adjuvants to target specific surfaces generating the desired wetting outcome. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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“…It may depend upon the nozzle and operating conditions as to whether there is a large effect or no difference. For example, using antidrift adjuvants ( Richardson & Ray, 1991), there was a large increase in flow with the disc and swirl plate nozzle for each solution, despite the solution viscosity being increased. In contrast, the flat fan nozzles with the antidrift adjuvant had little or no effect on flow.…”

Section: Formulation Characteristics and Effectsmentioning

confidence: 99%

Adjuvants and herbicidal efficacy – present status and future prospects

Zabkiewicz

2000

Weed Research

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The in¯uence of adjuvants on spray liquid behaviour and herbicide performance is reviewed. Total formulation ecacy can be expressed as a function of [deposition:retention:uptake: translocation:a.i. toxicity]. Adjuvants in¯uence the physico-chemical and plant interactions involved for each factor. Deposition eciency of spray droplets on to a target is dependent largely on the droplet spectrum, whereas retention performance is dependent on plant leaf surface character, orientation and canopy architecture, as well as droplet volume, velocity and dynamic surface tension eects. Uptake into plant foliage is aected by the leaf surface wax, cuticle age and composition and species variability. Uptake can be improved through appropriate formulation to provide either stomatal in®ltration or much greater and faster cuticular absorption of the active ingredient. The inherent translocation capability of the a.i. is not aected directly by adjuvants, which are relatively immobile, but they can increase the mass of absorbed a.i. translocated, as a consequence of improved uptake or may reduce it as a result of localized contact phytotoxicity. Considerable progress has been made in developing models of spray droplet deposition, adhesion and retention, as well as uptake. In future, individual models may be combined to provide an integrated formulation ecacy decision support system.

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The effect of spray thickening anti-drift adjuvants on flow rates through nozzles

Cited by 3 publications

References 0 publications

Importance of leaf surface and formulation properties in predicting wetting outcomes

Importance of leaf surface and formulation properties in predicting wetting outcomes

Importance of adjuvant formulation properties in predicting wetting on leaf surfaces

Adjuvants and herbicidal efficacy – present status and future prospects

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