Institute of Materials Science and Engineering, and Department of Materials & Mineral Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu 30011, Taiwan.
J Colloid Interface Sci. 2017 Nov 15;506:180-187. doi: 10.1016/j.jcis.2017.07.045. Epub 2017 Jul 17.
A newly designed dispersant for water-based suspensions, ammonium poly(methacrylate)-block-poly(2-phenoxyethyl acrylate) (PMA-b-PBEA), is proposed in this study. According to the results of rheological analysis, the dispersion efficiency of this new dispersant is superior to that of the commercially available ammonium polyacrylate (PAA-NH). The diblock structure of PMA-b-PBEA, which simultaneously contains a low-polar anchoring head group and a water-dissociable stabilizing moiety, is the main cause for its extremely high efficiency for powder dispersion. The unique structure not only results in effective adsorption approximately double that of PAA-NH, but also produces a low number of counter-ions that compress the electrical double layer and ruin powder stabilization. Based on Derjaquin-Landau-Verwey-Overbeek calculations, the large adsorbance of PMA-b-PBEA gives the powder, titania (TiO) in this study, a high steric stabilization energy. In addition, PMA-b-PBEA provides TiO with a remarkably high electrostatic energy because it generates fewer counter-ions. This energy provides excellent dispersity of powder in the suspensions with a high solid content of 60wt% without showing any rheological hysteresis.
本研究提出了一种新设计的水基悬浮液用分散剂，即聚（甲基丙烯酰胺）-嵌段-聚（2-苯氧乙基丙烯酸酯）（PMA-b-PBEA）。根据流变分析的结果，这种新分散剂的分散效率优于市售的聚丙烯酸铵（PAA-NH）。PMA-b-PBEA 的嵌段结构同时包含低极性锚固头基团和可水解析稳定部分，是其对粉末分散具有极高效率的主要原因。这种独特的结构不仅导致有效吸附量约为 PAA-NH 的两倍，而且产生的反离子数量较少，压缩了双电层并破坏了粉末的稳定性。根据德贾奎因-朗道-维尔韦-奥弗贝克（Derjaquin-Landau-Verwey-Overbeek）计算，PMA-b-PBEA 的大吸附量赋予了粉末（本研究中的二氧化钛（TiO））高的空间稳定能。此外，由于生成的反离子较少，PMA-b-PBEA 为 TiO 提供了极高的静电能。这种能量为高固含量为 60wt%的悬浮液中的粉末提供了极好的分散性，而没有表现出任何流变滞后现象。
