Influence of polymer dispersants on dispersion stability of nano-TiO₂ aqueous suspension and its application in inner wall latex paint

Abstract

The effects of SN5040 and polyethylene glycol(PEG) individually and in combination on the dispersion stability of nano-TiO₂ aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy. The adsorption mechanism of these dispersants was detected by zeta potential, isothermal absorption and FTIR analysis. It is found that SN5040 is superior for stabilizing nano-TiO₂ in aqueous suspension to PEG in basic region, and the optimum mass fraction of SN5040 addition is 3%. In the case of NaCl addition, the optimum value increases with the increase of NaCl concentration in the solution. When the mixture of SN5040 and PEG is employed, the antagonism appears preponderant. When SN5040 and PEG are added sequentially, the synergistic reaction takes place. The synergistic reaction can be attributed to the mechanism that PEG adsorption decreases the electronic repulsion between SN5040 molecules, which results in the increase of SN5040 adsorption density. PEG is adsorbed by the interaction with the pre-adsorbed SN5040 layer. Furthermore, the modified inner wall latex paint with well dispersed nano-TiO₂ suspension is endowed with excellent ultraviolet absorption and antibacterial properties.

Keywords

polymer dispersant / dispersion stability / nano-TiO₂ / inner wall latex paint / PEG adsorption