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Influence of Solid Fraction on the Optimum Molecular Weight of Polymer Dispersants in Aqueous TiO 2 Nanoparticle Suspensions
Author(s) -
Sato Kimitoshi,
Kondo Soichi,
Tsukada Mayumi,
Ishigaki Takamasa,
Kamiya Hidehiro
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.01906.x
Subject(s) - dispersant , suspension (topology) , chemical engineering , polymer , particle (ecology) , aqueous solution , zeta potential , materials science , viscosity , sodium polyacrylate , particle size , adsorption , colloid , nanoparticle , chemistry , chromatography , dispersion (optics) , composite material , nanotechnology , organic chemistry , raw material , oceanography , physics , mathematics , homotopy , geology , pure mathematics , optics , engineering
The effects of solid fraction and molecular weight of a polymer dispersant—sodium polyacrylate—on the apparent viscosity of an aqueous TiO 2 nanoparticle suspension were investigated by varying the particle solid fractions from 15 to 37 vol% and the molecular weight of the dispersant from 1200 to 30 000. When the solid fraction was increased, the molecular weight of the dispersant was decreased to obtain the lowest suspension viscosity. The effect of the molecular weight of the dispersant on the suspension viscosity was discussed based on the surface interaction between TiO 2 particles characterized by a colloid probe atomic force microscope. The polymer dispersant adsorbed on a particle surface enhanced the repulsive force between the TiO 2 particles and reduced adhesion by electrosteric interaction, which reduced the suspension viscosity. The size of the dispersant in the aqueous solution determined by a dynamic light scattering method was compared with the estimated particle surface distance. As the solid fraction increased, the average surface distance and the size of the dispersant attainable to the particle surface reduced; therefore, the optimum molecular weight of the dispersant for a dense suspension is also reduced.