New Polymeric Comb Dispersants for Agricultural Formulations: A Comparison of Performance in Pesticide Suspension Concentrates

A new family of dispersants for agrochemical suspension concentrate (SC) formulations has been created by reacting an anhydride-bearing resin with a methyl capped polyether amine. The result is a moderate molecular weight graft polyamide, with the desirable “comb” geometry. From this family of materials, four were chosen for comparison to three commercially available benchmark dispersants in several typical pesticide suspension concentrates. The criteria used to compare the new to the old dispersants were: ability to reduce suspension viscosity, zeta potential, syneresis, and tendency of the concentrate to “hardpack.” The study demonstrated that the new dispersants are generally very effective dispersants, but care must be used in selecting the best dispersant/wetting agent combination for a given pesticide formulation.