Pickering Emulsion Prepared by Asymmetric Adsorption on Montmorillonite

本論文研究方向是以蒙脫土以表面吸附陽離子型界面活性劑 , 雙十八碳長碳鏈之四級氯化銨 (dimethyl distearyl ammonium chloeide，DMDSAC)及吸附非離子型高分子聚乙烯?咯烷酮 (polyvinyl pyrrolidone，PVP）進行表面改質。利用不同界面活性劑來改變蒙脫土的表面性質，使改質蒙脫土成為一面親水一面親油之兩親性質，再將其作為水及甲苯系統之乳液穩定劑配製成皮克林乳液，探討DMDSAC、PVP分別與蒙脫土的重量比(D/M及P/M比)對乳液現象、粒徑、穩定性及相反轉之影響。 本研究中的系統分為兩大類：系統(I)為蒙脫土預先吸附PVP，再與DMDSAC配製成乳液；系統(II)為蒙脫土先與DMDSAC配製成乳液再添加PVP。 在系統(I)中可得知在蒙脫土含量足夠的情況下 (大於0.04 wt%)，乳液隨著D/M比降低有從W/O相反轉為O/W的情形發生。在0.04 wt%蒙脫土且固定P/M比為6.25之下，DMDSAC濃度由高至低，在相反轉前後乳液粒徑從167.6 μm上升至195.6 μm，最後下降至151.7μm，乳液粒徑呈現先上升後下降之趨勢，顯示穩定度呈先下降而後上升，原因為相反轉前連續相為油相，因此改質蒙脫土愈親油愈穩定，故降低D/M比乳液趨於不穩定，而相反轉後連續相轉為水相，此時改質蒙脫土變成愈親水愈穩定，因此降低D/M有助於乳液的穩定，此現象在其它0.04 wt%蒙脫土但不同P/M比下也能觀察到有相同趨勢出現。 系統(II)為蒙脫土先與DMDAC配製成乳液再添加PVP，在這個部分中，固定D/M比為0.33下改變P/M比，我們發現以蒙脫土濃度0.04 wt%配製之乳液相對於以0.02 wt%蒙脫土配製之乳液來的更穩定。我們用光學顯微鏡分析了以0.02 wt% MMT製備的乳液，但乳液在配完後5分鐘後即開始凝結及破裂，因此無法檢測到乳液粒徑。但在0.04 wt%蒙脫土之下，乳液會隨著P/M比自0.3上升到6.25，形狀由球型慢慢變為不規則形狀，乳液粒徑也從144 μm上升到175 μm。In this study , the research direction is aimed at the modification montmorillonite (MMT) surface by adsorbing the cationic surfactants, dimethyl distearyl ammonium chloride (DMDSAC) and nonionic polymer polyvinylpyrrolidone (PVP) to modifiy the MMT surface. This process can modify MMT with one surface hydrophilic and the other surface hydrophobic. This modified MMT was used to prepare water/toluene emulsion system. The effect of the weight ratio of DMDSAC and PVP to MMT (D/M、P/M ratio) on the emulsion type、diameter、stability and phase inversion was discussed. The preparation of Pickering emulsions are divided into two systems. System(I) is MMT pre-adsorbed PVP and then mixed with toluene containing DMDSAC to prepare the Pickering emulsions. System(II) is MMT pre-mixed with toluene containing DMDSAC to prepare the Pickering emulsion first and then add PVP into the Pickering emulsion. In System(I), it can be seen that the emulsion encounters the phase inversion from W/O to O/W with a decrease in D/M ratio and above 0.04 wt% MMT. Under the addition of 0.04 wt% MMT and fixed P/M ratio at 6.25, we found that as the concentration of DMDSAC decreased from high to low , the particle size increased from 167.6 μm to 195.6 μm , and finally decreased to 151.7 μm when phase inversion occurred. This trend shows that the emulsion stability decreases first and then increases. The reason is explained that when the continuous phase before the phase inversion is the oil phase, the higher D/M ratio causes the modified MMT more hydrophobic and leads the emulsion stable. However, after the phase inversion , the continuous phase transforms into the water phase, and the modified MMT becomes more hydrophilic and more stable with the reduction of D/M ratio. Hence, the reduction of D/M ratio will contribute to the enhance of stability of emulsion. This phenomenon can also be observed in other P/M ratios for 0.04 wt% MMT. In system(II), Pickering emulsions were prepared by mixing MMT suspension and toluene containing DMDSAC. Then PVP solution was added to make the emulsions. With D/M ratio fixed at 0.33 and P/M ratio between 0.15 to 6.25, the difference of emulsions was studied for 0.02 wt% and 0.04 wt% MMT. Observed by the optical microscope, the emulsions prepared by 0.02 wt% MMT were broken within 5 minutes. When the emulsions were prepared at 0.04 wt% MMT, with the increase of P/M ratio from 0.3 to 6.25, the diameter of droplets was increased from 144 to 175 μm.摘 要 i 表目錄 vi 圖目錄 vii 一、緒論 1 1.1 皮克林乳液簡介 1 1.2 Janus particle 簡介 2 1.3 奈米蒙脫土 (MMT)簡介 2 1.4 有機化改質黏土 (Organo-Clay) 3 1.5 乳液及乳化原理簡介 4 1.6 研究方向 6 1.7 實驗研究架構與流程 7 二、文獻回顧 9 2.1 蒙脫土吸附PVP高分子 9 2.2 改質蒙脫土配製皮克林乳液相關文獻 9 2.3 以Laponite配製皮克林乳液相關文獻 12 2.4 以其他固體粒子製備皮克林乳液相關文獻 15 三、實驗 18 3.1 實驗材料 18 3.2 實驗儀器 19 3.3 實驗步驟 20 四、結果與討論 22 4.1 蒙脫土吸附PVP 23 4.1.1. 熱重損失分析 (TGA) 23 4.1.2. 蒙脫土吸附PVP之吸附量計算 24 4.1.3. 蒙脫土吸附PVP之XRD分析 25 4.1.4. 蒙脫土預先吸附PVP，再與DMDSAC配製乳液XRD分析26 4.2 系統(I)：蒙脫土預先吸附PVP，再與DMDSAC於水/甲苯系統配製乳液 28 4.2.1. 固定蒙脫土總重及P/M = 0.3及D/M = 0.33，改變水相體積28 4.2.2. 固定0.04 wt% MMT及P/M = 6.25；改變D/M比 30 4.2.3. 固定0.04 wt% MMT及P/M = 3；改變D/M比 33 4.2.4. 固定0.04 wt% MMT及P/M = 0.3；改變D/M比 35 4.2.5. 固定0.04 wt% MMT及D/M = 0.33；改變P/M比 37 4.2.6. 固定0.02 wt% MMT及P/M = 0.3；改變D/M比 39 4.2.7. 固定0.02 wt% MMT及D/M=0.33；改變P/M比 41 4.2.8. 固定P/M=0.3及D/M=0.33；改變蒙脫土濃度 42 4.3 系統(II)：蒙脫土先與DMDSAC配製成乳液後，再加入PVP 44 4.3.1. 固定0.02 wt% MMT及D/M=0.3；改變P/M比 44 4.3.2. 固定0.04 wt% MMT及D/M=0.3；改變P/M比 46 五、結論 50 六、參考文獻 5