Research scientist and project leader, Government of Canada, Sault Ste. Marie, Ontario
Pages: 20 Published: Jan 1987
A study of viscosity-temperature, viscosity-volatility, and viscosity-shear rate relationships was carried out for aqueous formulations of pesticides and adjuvants, in order to understand the influence of intermolecular interactions on physical properties. The data showed a general trend that highly viscous formulations exhibit high viscosity-activation energy, low volatility, and high pseudoplasticity, although there were many exceptions to this trend. The volatility data indicated that the mechanism of evaporation of water from the medium involves intermolecular forces that are different from those encountered in pseudoplastic behavior and viscosity changes with temperature. Among the four surfactants studied—Triton X-114, Triton X-100, Atlox 3409F, and Tween 80—Triton X-114 was unique in providing highly viscous and pseudoplastic formulations. The study also indicated that a highly viscous formulation with low pseudoplasticity may pose problems in flowability and fine atomization in the nozzle systems. A high evaporation rate implies rapid evaporation of water from the fine droplets emitted in ultralow-volume (ULV) applications, indicating the potential for off-target drift problems.
viscosity, viscosity-activation energy, volatility, pseudoplasticity, viscosity-shear rate relationship, pesticide formulation, pesticides
Paper ID: STP19398S