Comparison of Good & Bad Plastic Parts by FTIR

Technique Used:  Fourier Transform Infrared Spectroscopy (FTIR)

Two plastic parts were submitted for analysis. One of the parts had fractured during use. The purpose of the analysis was to determine the difference between the "good" and failed parts. A sample of the material comprising each part was analyze by FITR and compared. The bulk of the materials comprising the two parts were very similar by FTIR. The parts were then soaked in isopropyl alcohol. The alcohol was decanted, then evaporated. The remaining residues from the two extracts were then analyzed using attenuated total reflectance (ATR) FTIR. The spectra obtained can be seen in the figure below. Each of the extracts contained dioctylphthalate (DOP, a common plasticizer), however the amount extracted from the fail part was much less than that extracted from the good part. The failure was due not enough plasticizer present in the "bad" parts.