STUDY OF THE LIPID DETERGENCY PROCESS AS OBSERVED BY THE QUARTZ MICROBALANCE METHOD

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Chemical solubilization of lipids is an imlportant process in the soil removal of textiles. This study will report a real time observation of the removal-process of solid lipids, namely, tripalmitin, trimyristin, cetyl alcohol, palmitic acid and lard from the surface of gold electrode of a quartz crystal microbalance by some anionic and nonionic surfactants. The surfactants were added in the bathing solutions of pH 7.0-12.5 at 25 and 30℃ over wide concentration ranges covering their cmc's. The lipids first swell up to about half of the weights and then are removed at rates specific to the surfactant species, thier concentrations and the pH's. The removal takes place from sufficiently below the cmc's, indicating that the micelles not necessarily participate in the solubilization process. With the anionic surfactants, the rates level off over their cmc's, while with the nonionic surfactants, the rates increase further in the concentration ranges. Alkalinity of the bathing solutions enhances the swelling degree and the removal rate to sizable degrees. These observations will be discussed for the interpretation of the molecular process of the lipid removal, 1. The removal process has been observed as the swelling of the solid lipids followed by the solubilization by the surfactants in non-micellic form. 2. The lipids swell more with increasing pH and increasing surfactant concentration. 3. The lipid removal takes place definitely from below the cmcs of the surfactants. With anionic surfactants, the apparent removal rate levels off over the cmcs while with nonionic surfactants, the rate increases further. 4. The process of the elimination of the substrate adipose dirt and the viscosity change of the appearance could be observed by measuring frequency and an admitance.