THE EFFECT OF ELECTROLYTES ON THE CLOUD POINT OF MIXED-SOLUTIONS OF POLYPROPYLENE GLYCOL AND IONIC SURFACTANTS

The cloud points of polypropylene glycol (PPG) in the presence of small amounts of ionic surfactants, including dodecyltrimethylammonium bromide (DTAB), cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and sodium cetyl sulfate (SCS) have been determined. The results show that the cloud point of PPG will be elevated if a certain amount of ionic surfactant is added. The longer the hydrocarbon chain length of the ionic surfactant homologues, the stronger the effect is, and the effect of anionic surfactants is stronger than that of cationic surfactants with the same hydrocarbon chain length. The cloud point remains unaltered on addition of the same amount of inorganic salt. When salts are added to the PPG solution in the presence of a certain amount of ionic surfactants, the cloud point decreases in a ratio depending on the concentration of salts, the nature of the ions and the valency of the ions with charges opposite in sign to the charges of the surface-active ion.Chemistry, PhysicalSCI(E)EI8ARTICLE139-473