- 期刊
Polyelectrolyte-Surfactant Interaction and Its influence on Flocculation and Coalescence of Oil-in-Water Emulsions
聚電解質與界面活性劑之交互作用及其對水中含油乳液的凝聚與併合作用之影響
摘要
本文主要利用沉澱與再溶解方法探討陽性聚電解質與陰性界面活性劑十二烷基硫酸酯鈉之交互作用，其中主要複合作用的驅動力來自於兩者間之電荷中和反應，並以矽油乳液作為模型系統，我們探討安定化與去安定化的各種控制因素，包括界面活性劑濃度、凝聚劑濃度、油滴粒徑、界面張力及界他電位等，發現陰性界面活性劑十二烷基硫酸酯鈉之添加，使乳液油滴表面具有負值之界他電位，可維持矽油乳液之分散安定性。另外應用陽性聚電解質之添加，與陰性界面活性劑反應生成油與水非溶解性的複合體，因而破壞乳液之安定作用力，發現最適當之凝聚劑濃度，與界面活性劑濃度成正比，且與聚電解質本身之電荷密度成反比，若利用間歇性方法添加兩種含中低電荷密度之混合型凝聚劑，則同時發生電荷中和反應與高分子架橋反應兩種機制之協力效果，其促進乳液聚與併合的功能，較優於單一型凝聚劑。
關鍵字
無資料並列摘要
The strong interactions between the cationic polyelectrolyte and the anionic surfactant sodium dodecyl sulfate were characterized by means of precipitation and redissolution study in aqueous solutions. The main driving force for the association complexation between two components is the electrostatic charge neutralization. By using silicone oil-in-water emulsions as a model system, we present the factors the influence the stabilization and destabilization of the emulsions: surfactant concentration, flocculant concentration, oil droplet size, interfacial tension and zeta potential. Cationic polyelectrolytes were used as a flocculant to destabilize the emulsion by reacting with the anionic surfactant sodium dodecyl sulfate to form an insoluble complex. The optimum flocculation concentration of cationic polymer required for neutralizing the negative charges of surfactant increases proportionally to the concentration of surfactant but inversely proportionally to the charge density of polymer. Flocculation and coalescence of emulsion with a dual polymer combination of moderate and low cationic charge densities with an intermittent dosing method is compared with a single polymer system. Analysis of the turbidity removal and coalescence results under corresponding conditions showed that the dual polymer system produces an appreciably better destabilization of emulsions through a synergistic combination of electrostatic charge neutralization and polymer bridging mechanisms.