The stability of emulsions in the presence of additives

Abstract

The influence of different additives on the effectiveHLBvalues of non-ionic emulsifiers was studied by the method of the determination of the phenol index values and by the determination of the emulsion inversion point in the system with xylene as the oil phase. Ethanol, glycerol and ethylene glycol were investigated as additives. The method of the determination of the phenol index value was applied on two homologous series of non-ionic emulsifiers: nonylphenolpolyglycolethers with 10, 15, 23 and 30 moles of bound ethylene oxide and polyglycolethers of fatty alcohols (C16–C18) with 15, 20 and 23 moles of bound ethylene oxide. The additives were applied in the concentration of 5, 10, 15 and 20 %. The results showed that ethanol and ethylene glycol increased the phenol index value. The influence of ethanol was more pronounced. On the contrary, glycerol reduces the phenol index value. There were small differences in the influence of these additives on certain members of both homologous series, but the general trend is presented here. The influence of the same additives on the values of the emulsion inversion point was investigated in the system with xylene and nonylphenolpolyglycolethers with 10 moles of bound ethylene oxide. Ethanol and ethylene glycol were applied in the concentrations of 1, 5, 10 and 15 % and glycerol in 5,7.5,10 and 15 %. The results showed that ethanol and ethylene glycol reduce the emulsion inversion points, while glycerol increases them. On the basis of these investigations it can be concluded that ethanol and ethylene glycol could contribute to an increase in the stability of emulsions, glycerol has the opposite effect. The results of both applied methods are in accordance.

Keywords

• additives
• emulsion
• phenol index value
• emulsion inversion point.