FIBRE STRUCTURE IN DISPERSIONS OF SOAP IN MINERAL OIL

Abstract

The texture and other physical properties of soap dispersions in mineral oil, or lubricating greases, depend largely on the degree of dispersion of the soap. Calcium and aluminium soap dispersions yield in general a very short unctuous texture owing to the small size of the soap fibres in these systems. Sodium soap dispersions show a wide range of texture from a smooth to a very fibrous character, and this is related to the dimensions of the soap fibres in the dispersion.A novel method of examination of these fibres is described, and this procedure is compared with other means. Data and photographs of soap fibres are shown.The development of large fibres is discussed and the growth of fibres by orientation and overlapping of smaller fibrils is described. Evidence is adduced by micro-manipulator examination of soap and non-soap fibres in mineral oil. The effect of glycerol, present in greases manufactured from fats, is shown to be essential for the production of long fibres in ordinary practice, and this effect is ascribed mainly to the ability of oil to wet the soap in the presence of glycerol.