Forensic calorimetry

Though methods for identification of man-made fibers utilizing differential scanning calorimetry, differential thermal analysis, and thermogravimetric analysis have been reported, the sample amounts required are too large for actual case studies, so these methods are rarely used in forensic identification and are only adopted in very specific cases. 

A forensic sample consisting of melt-recrystallised polymers recovered from the scene of a fire in a factory is identified by differential scanning calorimetry. The factory commonly used two kinds of film sheets, A and B, made by different manufacturers. It is necessary to decide whether the forensic sample related to material A or B. The forensic sample and reference samples of materials A and B are subjected to IR spectroscopy and pyrolysis gas chromatograph mass spectrometry measurements, which reveal their PE nature. The thermal behaviour of the samples is examined by differential scanning calorimetry (DSC) and they are found to be blends of two kinds of PEs, LDPE and LLDPE. The samples can be identified and distinguished from each other via the DSC measurements. 6 refs. 

---