Evaluation of Present Methods of Determining the Soap Content of Greases

摘要

Three methods of analysis were compared. They were: ASTM Method D128, ASTM D128 Supplementary Method using a Soxhlet apparatus with a paper extraction filter and a variation of ASTM D128 by substituting ten percent acetic acid for ten percent hydrochloric acid as the initial breakdown acid. The following information was obtained from this investigation: (1) The supplementary method of ASTM D128 has the best repeatability of the three methods evaluated except when used in the breakdown of an aluminum soap thickened grease. (2) There is no significant trend as to which acid breakdown method is better from the point of repeatability. (3) The digestion time is shortened by substituting acetic acid for hydrochloric acid as the initial breakdown acid except in the analysis of an aluminum soap thickened grease. (Author)