| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 99 === This study investigates latex particle size control and colloid stabi
-lity for semi-batch styrene/2-ethylhexyl acrylate emulsion polymerizati
-on. The effects of the the hydrophilic property of monomer emulsion feed and the mixed poly -mer/nonionic (B-2/#5090) surfactants are investigated.
Experimental data show that increasing monomer hydrophilicity results in a decreasing the particle size (Monomer hydrophilic ability, MMA>ST>2-EHA). In the semi-batch emulsion copolymerization, styrene/2-ethylhexyl acrylate system shows bigger particle sizes than methyl methacrylate/2-ethylhexyl acrylate system. The concentration of surfactant during the particle nucleation period plays a very important role. The result shows that the particle size decreases with increasing the concentration of surfactants. However, changing the concentration of non-ionic surfactants (#5090) do not change the particle size significantly. The concentration of polymeric surfactant (B-2) is the most important parameter in the semi-batch styrene/2-ethylhexyl acrylate emulsion polymerization.
In the semi-batch emulsion copolymerization, styrene/2-ethylhexyl acrylate system and methyl methacrylate/2-ethyl -hexyl acrylate system are very stable, as show by the very small amount of scrap. Moreover, the surface of colloidal particles absorbs surfactant (B-2/#5090) is not enough; it will lead to reduce colloidal stability.
|
|---|
