Effect of amphoteric dispersant on the dispersion properties of nano-SiO2 particles

An amphoteric polycarboxylate dispersant (APC) was synthesized by copolymerization of acrylic acid (AA), methacryloxyethyltrimethyl ammonium chloride (DMC), and isopentenol polyoxyethylene ether (IPEG). The molecular structure of APC was characterized by FT-IR, H-1-NMR, and GPC. Effect of the dosage of APC on the rheological performance of nano-SiO2 suspension was investigated by measurements of the plastic viscosity. The results indicated that the best dispersion effect of APC was obtained when the dosage of APC was about 10 wt % (by the weight percent of nano-SiO2), which can maintain the dispersion of nano-SiO2 suspension uniformly for 4 h without settlement. Meanwhile, the zeta potential value on the surface of nano-SiO2 particles shows that the better dispersion performance of APC was attributed to the solvation water film formed by the polyoxyethylene side chains and the electrostatic repulsion formed by positively groups (C equivalent to N+) on the APC structure combined with -SiO- groups on the surface of nano-SiO2 particles. (C) 2017 Wiley Periodicals, Inc.