Role of Heat Treatment on the Performance of Polymers as Iron Oxide Dispersants

Abstract The influence of heat treatment on the performance of various polymers as iron oxide dispersants in an aqueous system has been investigated. The polymers evaluated include: homo-polymers of acrylic acid, methacrylic acid, maleic acid; co-polymer of, acrylic acid:2-acrylamido-2-methylpropane sulfonic acid; ter-polymers of acrylic acid:2-acrylamido-2-methyl propane sulfonic acid:sulfonated styrene, and acrylic acid:2-acrylamido-2-methylpropane sulfonic acid:t-butylacrylamide. It has been found that all polymers lose performance to a varying degree when exposed to thermal treatment (150°C, 200°C, 20hr). The performance data also suggest that sulfonated styrene containing ter-polymer is a better iron oxide dispersant than the ter-polymer containing 2-acrylamido-2-methylpropane sulfonic acid and tertiary butylacrylamide. In the case of co-polymer of acrylic acid:2-acrylamido-2-methylpropane sulfonic acid, the thermal treatment exhibits strong negative influence on the dispersancy power of the polymer. The results have been explained in terms of loss of 2-acrylamido-2-methylpropane sulfonic acid and t-butylacrylamide in the co- and ter-polymers, as determined by FT-IR and NMR methods, leading to the formation of poly(acrylic acid).