Thermogravimetric Analysis as a Polymer Identification Technique in Forensic Applications

Abstract

This paper investigates the potential of thermogravimetric analysis (TGA) as a tool for determination of different species of polymers. Materials analyzed include polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polystyrene, polypropylene, nitriles, and nylon. Analyses showed excellent discriminating results even when samples were contaminated with silicates, organics, moisture, and char. The techniques developed were designed with a forensic-type analysis in mind, such as analysis of blast fragments and arson debris. Techniques were developed that gave satisfactory results even when sample sizes were less than five milligrams.

A quantitative differentiation method for plastic bags by infrared spectroscopy, thickness measurement and differential scanning calorimetry for tracing the source of illegal drugs

“…Plastic bags are used to conceal body parts of a victim or other crime related materials [1] and to pack illicit drugs [2][3][4] and may be of interest in arson related investigations [5,6]. In particular, a thorough examination of the packaging used to contain drugs can help in tracing their source.…”

“…Polymers are quite versatile materials under this point of view, because slight variations in the production process may bring about a variety of differences in chemical and physical properties that may be exploited for forensic science purposes [6][7][8][9][10][11][12].…”

A method based on thermogravimetry/differential scanning calorimetry for the forensic differentiation of latex gloves

“…The usefulness of this technique for forensic purposes and in material analysis has already been suggested [11,12]. Thermal degradation of polymer materials depends on their formulation and slight variations in additivation can bring about measurable changes in their behavior at high temperatures [13].…”

Forensic characterization of HDPE pipes by DSC

“…Forensic identification and characterization of soil samples, candle waxes and polymers/plastics by DTA/TGA were done by many workers [5][6][7][8]. Ionashiro et al [9] used DSC to study the thermal behavior of hair samples and verified the possibility of identifying an individual based on DSC curves from a data Bank.…”