Research Specialist, The Agricultural Group of Monsanto Company, St. Louis, MO
Pages: 11 Published: Jan 1993
A major limitation to the use of alkyl glycosides as surfactants for liquid glyphosate formulations is their unacceptable degree of foaming when diluted in the spray tank. I have found that certain acetylenic diol surfactants can be used as defoamers in glyphosate formulations with an alkyl glycoside. The acetylenic diol surfactant was completely solubilized by the alkyl glycoside in the concentrated formulation. Therefore it remained homogeneously distributed throughout the formulation. This overcomes a severe limitation of using conventional defoamers, such as those based on silicone, with water soluble concentrates, since they are not soluble in the formulation and will separate with time. When the formulation was diluted to spray solution concentrations the acetylenic diol surfactant became apparently insoluble (the solution was hazy) and it functioned as a defoamer. The relative defoaming ability of three acetylenic diol surfactants from Air Products, called Surfynol® surfactants, in a liquid glyphosate formulation containing Henkel APG 325 surfactant, was Surfynol 110D > Surfynol 104 ≫ Surfynol 420.
glyphosate, alkyl glycoside, acetylenic diol, defoamer
Paper ID: STP25120S