Interaction between hydroxypropylcellulose and surfactant and its effect on dispersion stability of kaolinite suspension in an aqueous phase

Abstract

Both sodium dodecylsulfate (SDS) and cetylpyridinium chloride (CPC) formed a complex with hydroxypropylcellulose (HPC) due to hydrophobic interaction. Binding ratio of a surfactant to HPC, reduced viscosity and cloud point of an aqueous solution of HPC were obtained as a function of the surfactant concentration. Intramolecular/ intersegment bridging was speculated at low concentrations of both surfactant and HPC, which resulted in shrinking of the polymer coil. On the other hand, at high concentrations of the surfactant, micelle-like aggregate was formed along the polymer chain p-dimethylamino-azobenzene was solubilized in this aggregate. The surface complex was formed on kaolinite particles. Anomalous flocculation of the suspension was observed at a specific mixing ratio of SDS to HPC by virtue of the interparticle bridging by the complex. The flocculation was detected by the measurements of mean diameter of secondary particles and rheological parameters such as Bingham yield values, and apparent and plastic viscosities. The contour lines for these parameters were obtained as a function of the concentrations of SDS and HPC.