Abstract:

Four kinds of quaternary ammonium salt cationic surfactants(dodecyl benzyl dimethyl ammonium chloride(1227), tetradecyl dimethyl benzyl ammonium(1427), hexadecyl trimethyl ammonium bromide(1631) and octadecyl trimethyl ammonium bromide(1831)) were used to modify sodium bentonite(Na-Ben). The prepared organic bentonites(1227-Ben, 1427-Ben, 1631-Ben, 1831-Ben) were characterized by Fourier transform infrared spectroscopy(FT-IR) and X-ray diffraction(XRD), and used as subsidence-resistance for preparing suspensions containing 5% hexaconazole. The suspension capability of bentonite modified by above four organic additives in water and the effects of these bentonites on the physical stability of suspensions were examined. FT-IR spectra and XRD analysis results showed that these four cationic surfactants were intercalated into the layer of bentonite. Suspension capability results indicated that 1831-Ben has a better suspension than the other three. Subsidence-resistance tests showed that bentonites modified by organic additives could improve the physical stability of suspensions. The water segregation ratio of samples prepared by 1831-Ben was the lowest, while the viscosity, yield value and suspension rate were the highest. So 1831-Ben could be used as a suspension-additive for the preparation of suspensions containing 5% hexaconazole.

Key words: Organically-modified bentonite, hexaconazole suspension concentration, rheological characteristics, physical stability