Two polymer dispersants, polyester dispersant (PD) and sodium polyacrylate (NaPAA), were used to disperse titanium dioxide in 10% aqueous isopropyl alcohol (IPA). The effect of pH and zeta potential on the dispersibility of the titanium dioxide (TiO₂) was studied via sedimentation. An optimum pH value of 8 for the two polymer dispersants in aqueous IPA suspension was found. The isoelectric point of the TiO₂ particles was at pH 5.1 and pH 5.3 and shifted to lower pH in the presence of PD or NaPAA, with a greater decrease in zeta potential for the NaPAA suspension (− 36.5 to − 64.1 mV) due to the high degree of ionization compared with PD (− 36.5 to − 60.6 mV). The conformations of PD and NaPAA were strongly pH dependent: Their adsorption was highest at low pH and lowest at high pH, with the maximum adsorption of PD and NaPAA being 44.0 and 39.2 mg g⁻¹ at pH 3, respectively. It was shown that the stability of the suspensions was not only dependent on the pH but also on the zeta potential and molecular structure of the dispersant.

中文翻译：

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高分子分散剂在异丙醇水溶液中二氧化钛的分散稳定性

使用两种聚合物分散剂，即聚酯分散剂（PD）和聚丙烯酸钠（NaPAA），将二氧化钛分散在10％的异丙醇水溶液（IPA）中。通过沉降研究了pH和ζ电位对二氧化钛（TiO ₂）的分散性的影响。发现两种聚合物分散剂在IPA水性悬浮液中的最佳pH值为8。TiO ₂的等电点颗粒的pH值为5.1和pH 5.3，并在存在PD或NaPAA的情况下移至较低的pH，与PD相比，NaPAA悬浮液的Zeta电位下降幅度更大（− 36.5至-64.1 mV）， （− 36.5至− 60.6 mV）。PD和NaPAA的构型与pH密切相关：在低pH值时吸附最高，在高pH值时最低，PD和NaPAA在pH 3时的最大吸附分别为44.0和39.2 mg g ^-1。结果表明，悬浮液的稳定性不仅取决于pH，而且取决于ζ电位和分散剂的分子结构。