1996 Volume 1 Issue 1 Pages 27-31
In recent serious crimes, such as murder, burglary or rape, pressure sensitive adhesive cloth tapes (PSAT) are frequently used for binding hands and feet, gagging and blindfolding, or packing of important physical evidence including the bodies of murder victims.
For the forensic indentification of PSAT, color examination, backing cloth examination, Fourier transform infrared spectroscopy (FT-IR) and pyrolysis gas-chromatography (Py-GC) have been reported.
In this paper, discrimination of PSAT by ash content and elemental ratio of adhesives was studied. Fifty-seven PSAT samples obtained from 20 manufacturers were subjected to yarn density measurements.
Further analyses of ash and elemental contents of adhesives was conducted by thermogravimetric analysis (TGA) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS), in the undistinguished tapes by yarn density measurements. A Combination of the data from measurements of yarn density, adhesive ash content and Ti/(Ca+Ti) ratios enabled us to classify the 57 PSAT samples into 36 groups.
Though exposure of PSAT to the atmosphere or water for 24 weeks showed essentially no effect on ash contents and Ti/(Ca+Ti) ratios, except for exposure to an acid solution (pH<1).
Applied together with conventional techniques, such as color examination, FT-IR and Py-GC, the techniques reported here can increase the discrimination capability of forensic analyses.
