ISSN: 0022-1198
CODEN: JFSCA
Page Count: 12

The Characterization of Plastic Automobile Bumper Bars Using Fourier Transform Infrared Spectroscopy (FTIR), Pyrolysis Gas Chromatography (PGC), and Energy Dispersive X-Ray Microanalysis Combined with a Scanning Electron Microscope (SEM-EDX)
Parybyk, AE
Senior forensic scientist and chief forensic scientist, Forensic Science Centre,

Kobus, HJ
Senior forensic scientist and chief forensic scientist, Forensic Science Centre,

Abstract

A collection of 28 plastic automobile bumper bars has been examined using Fourier transform infrared spectroscopy (FTIR), pyrolysis gas chromatography (PGC), and energy dispersive X-ray microanalysis combined with a scanning electron microscope (SEM-EDX). FTIR identified 8 polymer classes in the collection. Polypropylene-based (PP) plastics and polyurethane (PUR) plastics were the most common with approximately three quarters of the samples being of these types. PGC provided additional discrimination between the samples in the collection, particularly for the PUR samples, defining a total of 13 categories. SEM-EDX was the most discriminatory technique used and resulted in 17 categories being identified. However, the combination of the 3 techniques of FTIR, PGC, and SEM-EDX was recommended as the preferred approach as it provided a high degree of discrimination with 25 categories identified. Vehicle identification via analytical profiles of bumper bar materials was not possible, and consequently, the establishment of a database using such information for investigative purposes could not be recommended.

Keywords:
criminalistics, automobiles, plastics, spectroscopic analysis, chromatographic analysis, X-ray analysis

Paper ID: JFS12830J
DOI: 10.1520/JFS12830J
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