NCJ Number
217647
Journal
Journal of Forensic Sciences Volume: 52 Issue: 2 Dated: March 2007 Pages: 335-340
Date Published
March 2007
Length
6 pages
Annotation
Since the handling of plastic-bonded explosives such as composition C-4 (RDX plus binders) and Semtex-H (PETN and RDX plus binders) is expected to produce fingerprint residues that contain particles of explosives on objects such as clothing, hair, and luggage, this study examined the particle sizes of the explosives in both C-4 and Semtex-1A fingerprints.
Abstract
The study found a target particle size of 10 mm or larger, with the maximum particle sizes being 50-100 mm; however, if processing conditions have reduced the largest particle size in the plastic-bonded explosive, the largest particle size in the residue will also be reduced. Particle size is one of the factors that affects the performance characteristics of explosives, and various recrystalization processes may be used to control the mean particle size and the particle size distribution. A future study will examine a large sample set of plastic-bonded explosives in order to determine the variability in maximum particle sizes in residues due to variability in the starting materials. In addition, mechanisms of transfer other than by fingerprints will be considered. The fragmentation properties of RDX and PETN were determined by extracting explosive crystals from samples of plastic explosives, crushing them, and then sizing the particles with scanning electron microscopy. From these data, the fractal dimensions could be evaluated in order to determine the distribution of mass with particle size. Additional experiments were conducted by handling the plastic explosive and forming fingerprints from residues left on the hands. Polarized light microscopy was used to size the explosive particles in the fingerprints. 5 figures and 28 references