Synthesis of sodium polyacrylate copolymers as water-based dispersants for wet ultrafine grinding of cobalt aluminate particles

摘要

Sodium polyacrylate copolymers, i.e., polymethyl methacrylate-methacrylic acid-2-acrylamido-2-methylpropane sulfonic acid-hydroxyethyl methacrylate (PMASH(S)) were synthesized with polymethacrylic acid-2-acrylamido-2-methyl propane sulfonic acid-hydroxyethyl methacrylate (PASH) as water-based dispersants for ultrafine grinding of cobalt aluminate (CoAl2O4) particles in a stirred bead mill. The product size/size distribution, suspension rheological properties, electrokinetic potential and adsorption behavior were analyzed by laser particle size analysis, rheometry, thermogravimetry and electrokinetic potential measurement, respectively. Dispersant PMASH(1) used for grinding the pigment particles for 120 min gives an increased product fineness with a narrower particle size distribution. This is possibly due to the presence of solvated chains of dispersant PMASH(1) on the particle surface generating a proper steric hindrance energy between the particles. Besides, the breakage behavior of CoAl2O4 particles in ultrafine grinding was also discussed by selection and breakage functions from population balance modeling, indicating that the addition of dispersant PMASH(1) in ultrafine grinding has a greater grinding efficiency. The breakage mechanism of the pigment particles in the bead mill is mainly abrasion, accompanied by compression.

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