title: Using paint to investigate fires: an ATR-IR study of the degradation of paint samples upon heating.
abstract: Fire investigation is a challenging area for the forensic investigator. The aim of this work was to use spectral changes to paint samples to estimate the temperatures to which a paint has been heated. Five paint samples (one clay paint, two car paints, one metallic paint, and one matt emulsion) have been fully characterized by a combination of attenuated total reflectance Fourier transform infrared (ATR-IR), Raman, X-ray fluorescence spectroscopy and powder X-ray diffraction. The thermal decomposition of these paints has been investigated by means of ATR-IR and thermal gravimetric analysis. Clear temperature markers are observed in the ATR-IR spectra namely: loss of ν(C = O) band, >300°C; appearance of water bands on cooling, >500°C; alterations to ν(Si-O) bands due to dehydration of silicate clays, >700°C; diminution of ν(CO3 ) and δ(CO3 ) modes of CaCO3 , >950°C. We suggest the possible use of portable ATR-IR for nondestructive, in situ analysis of paints.
authors.affiliation: Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, U.K.
authors.forename: Kelly
authors.initials: K
authors.lastname: Roberts
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Almond
authors.forename: John W
authors.initials: JW
authors.lastname: Bond
keywords: X-ray diffraction; fire scene investigation; forensic science; infrared spectroscopy; paint analysis; thermogravimetric analysis