Rapid characterisation and classification of automotive clear coats by attenuated total reflectance infrared spectroscopy

The effect of environmental degradation on the characterisation of automotive clear coats by infrared spectroscopy

“…These classes were found to be related to the country of vehicle manufacturer, and in some instances to specific year ranges or manufacturing plants [21]. This is significant as it allows the possible identification of vehicle class characteristics for a questioned paint sample recovered from a crime scene.…”

“…It should also be noted that as the samples were obtained from real vehicles rather being specifically prepared for this research, the exact composition of each clear coat was not known. However, previous work has established that clear coat formulations generally consist of acrylic, melamine, styrene and polyurethane polymers in varying proportions [21]. Analysis was conducted twice a week for 25 weeks, and again after 435 days of exposure.…”

“…At each analysis interval, 5 cm 2 sections were cut from the samples and stored in individual yellow A5 envelopes. A scalpel blade was then used to remove paint chips from each sample for infrared analysis [21,22].…”

“…An additional five samples selected at random from those collected for the previous studies [21,22] were stored under controlled office conditions for a period of one year, to determine whether any degradation would be observed in samples stored away from weather exposure. These samples were stored in the dark, with temperature remaining between approximately 21-23°C.…”

“…Earlier research by the authors Maric et al [21] employed attenuated total reflection infrared (ATR-IR) spectroscopy with chemometric analysis for the discrimination of automotive clear coats from a range of Australian and international vehicles, establishing a predictive model that could assign unknown clear coat samples into one of nine distinct classes [21]. These classes were found to be related to the country of vehicle manufacturer, and in some instances to specific year ranges or manufacturing plants [21].…”