PEGylated strategy for new polyurethane construction and its effects in improving the dispersion stability of tebuconazole suspension concentrate

Dispersants play an important role in improving the physical stability of the suspension. In this work, four polyurethane dispersants (PUDs) were successfully designed and synthesized by adjusting the dosage of DMPA and terminating with PEG (600, 800, 1000) through prepolymer dispersion method. Subsequently, 430 g/L tebuconazole suspension concentrate (SC) was selected to investigate the effects of different PUDs on the Zeta potential, particle size, suspension rate, viscosity, absorbance ratio and rheological properties. The results showed that the suspension system was the most stable when the dispersant dosage was 4 wt%. And the dispersion stability of tebuconazole SC prepared with PUD8–600 (8 wt% DMPA) is higher than that of prepared with PUD5–600 (5 wt% DMPA). Furthermore, the dispersion stability of tebuconazole SC is also significantly related to the molecular weights of PEG, in which that PEG-800 end-capped dispersant (PUD8–800) displayed best dispersion stability with low viscosity (187 mPa·s) and zeta potential (- 40.6 mV).