NCJ Number
134750
Journal
Journal of the Forensic Science Society Volume: 31 Issue: 4 Dated: (October/December 1991) Pages: 457-461
Date Published
1991
Length
6 pages
Annotation
Improvements and alternate methods for the identification of fiber types were examined using different solvents and melting point determinations.
Abstract
Forty-six authentic acetate fiber samples were tested with each of 8 different solvents. These included dichloromethane; chloroform; acetone; 50 percent formic acid; methyl acetate; 70 and 80 percent aqueous 1,4 dioxane; and 50 percent aqueous glacial acetic acid. The melting point of the fibers was determined by heating chopped fibers between two glass coverslips on a microscopic hot-stage. The temperature at which the fibers lost their cross-sectional shape and began to flow freely into one another indicated the melting point. The results of the solvent test demonstrated that dichloromethane and 50 percent aqueous formic acid provide unambiguous discrimination between di- and tri-acetate fibers. Diacetates are soluble in aqueous formic acid and are affected slightly by dichloromethane, whereas, the triacetates react in a reverse manner. Of the 28 diacetate samples, all except 2 melted within the range of 241-249 Centigrade degrees. Most of the triacetates had melting points about 300 degrees. The additional time required for the melting point determination suggests that the solvent tests will be more appropriate in most cases of analysis. 2 tables and 5 references