Study of Different Dispersants on Water-Based Titanium Dioxides Suspensions

• Main Authors: Che-Wen Tsai, 蔡哲文
• Other Authors: 蘇淵源
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/bz9kmk

碩士 === 國立臺北科技大學 === 化學工程與生物科技系化學工程碩士班 === 106 === Composite materials coated by paints with functional ingredients would have functional ability. Making paints have stable dispersibility is the basic demand; therefore, the purpose of this research is to study the dispersibility and suspending mechanism of titanium dioxide(TiO2) on water-based suspensions, and some samples would be added in polymer solvent, then observe that if those still keep the same dispersing characteristic as previous. Dynamic light scattering/zeta potential analyzer was operated to measure particle sizes and surface potential indicating the agglomerate behavior and the repulsion of zeta potential , rheometer was used to measure the change of viscosity indicating attractive force among particles, and thermogravimetric analyzer was operated to observe the adsorbed amount of the dispersant on TiO2. Then the isoelectric point (IEP) of TiO2 was found at pH=3, and untreated TiO2 didn’t have enough zeta potential to disperse evenly when pH<6. The anionic dispersant (PAANH4) didn’t work very well at pH=2 but at pH=4; the cationic dispersant (PEI) works well both at pH=2 and pH=4; adding 0.42wt% PEI into the suspension at pH=11 would cause agglomerate, but adding more about 0.84wt% into the suspension would recover its excellent dispersibility. In the adsorption experiment indicated that the acid environment would make PAANH4 have hydrogen bond with titanium dioxide so that increase the adsorbed amount; yet absorbed amount of PEI would increase with increasing pH values. After some samples were added into polymer solvent, the anionic dispersant did disperse the suspension of polymer solvent/TiO2 well, but the cationic dispersant caused the agglomerate because of its cations on TiO2 would attract polymer which have negative zeta potential, so the anionic dispersant is more appropriate to be used as TiO2 treatment in polymer solvent.