Semibatch MMA/2-EHA Emulsion Polymerization the Relation between Surfactants and Performance in Resisting Externally Added Electrolytes
| Autor: | Fu-en Yu, 余福恩 |
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| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 The objective of this work was to prepare polymer colloids via semi-batch MMA/2-EHA emulsion polymerization with mixed anionic and nonionic surfactants. The chemical stability of latexes toward added Mg2+ was investigated. It is well known that the anionic surfactant is very sensitive to cation and the nonionic surfactant is the major component used to resist the externally added electrolytes. Mackor theory predicts that the steric stabilization increases with increasing the adsorbed polymer chain length and the number of adsorbed sites per unit surfact area. however the experimental results show that the chemical stability of latexes toward added electrolytes in the best for the polymerizations with the nonionic surfactant with the shortest PEG chain length. This is primarily due to the secondary particle nucleation process occurring in the polymerizations nonionic surfactants with longer PEG chain length, there by leading to larger total particle surface area and smaller particle surface PEG density . |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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