Synthesis of comb-like polymeric surfactants with a tricyclic rigid core and their use as dispersants in pymetrozine water suspension concentrates

Abstract

Comb-like polymeric surfactants with a tricyclic rigid core have been synthesized from rosin. Their structures were confirmed by IR and ¹H NMR spectroscopies and GPC. The surface activities of these surfactants were evaluated according to critical micelle concentration (CMC), the surface tension at CMC (γ_CMC), emulsification properties (EP), and foam properties (FP). Their CMC values were 0.004–0.023 g L⁻¹, which were much smaller than those of the surfactant without a rigid core (14.59 g L⁻¹). Measurement of the rheological properties revealed that the surfactant solutions at 50 g L⁻¹ were dilatant fluids. A break point in the viscosity–shear rate curve moved to a high shear rate when the proportion of the monomer with a rigid core increased. The dispersing and stabilizing properties of these surfactants as dispersants were investigated to prepare pymetrozine water suspension concentrates. The results indicated that surfactants with a rigid core had good grinding and dispersion effects, the suspension rate of the pymetrozine water suspension concentrates was higher than 95%, and the water suspension concentrates had good stability during the cold storage process. The introduction of a rigid core into polymeric surfactants can effectively improve the surface activities of these surfactants and the suspension rate and stability of water suspension concentrates.