Effect of octadecylamine polyoxyethylene ether on the adsorption feature of sodium polystyrene sulfonate on the SiC surface and the relevant dispersion stability of slurry

Silicon carbide (SiC) is a widely used advanced ceramic material. Due to the electrostatic repulsion between anionic polyelectrolyte and SiC surface, the adsorption capacity of anionic polyelectrolyte sodium polystyrene sulfonate (PSS) is small, so it is difficult to achieve good modification effect. It is very important to improve the adsorption capacity of PSS on SiC surface. In this paper, we used non-ionic surfactant octadecylamine polyoxyethylene ether (AC1830) and anionic polyelectrolyte PSS as dispersant to modify SiC powder. The adsorption of AC1830 is not affected by the surface charge and can shield part of the charge, which can be used as the adsorption site of PSS to promote the adsorption of PSS on SiC surface. The 50 vol% SiC slurry with viscosity of 0.039 Pa s was produced, which was suitable for slip casting. Zeta potential method showed that the isoelectric point (IEP) of SiC powder modified by this method shifts to the left obviously. The sedimentation experiment shows that the dispersion stability was significantly improved. Contact angle measurements showed that the modifier was successfully adsorbed on the surface of the powder and provided hydrophilic groups, which improved the wettability of the powder. The results of adsorption measurement showed that the isothermal adsorption model and kinetic adsorption model of PSS for SiC powder and SiC powder modified by AC1830 conform to Langmuir model and pseudo-second-order (PSO) model. The adsorption of AC1830 on SiC surface improves the adsorption capacity of PSS.