FTIR can identify unknown plastic materials by comparison with known materials (i.e. from a spectral library).
Fig. A – Sample A FTIR spectrum compared with Nylon 6/6 and Nylon 6/9. Part of the spectrum
is more similar to Nylon 6/6 and part is more similar to Nylon 6/9.
This is the Fourier Transform Infrared (FTIR) spectrum of an unknown plastic (bottom) compared with library spectra of Nylon 6/6 and Nylon 6/9 respectively. The spectrum suggests that this is likely a blend of Nylon 6/6 and Nylon 6/9.
Carl Nail says:
The spectrum for the unknown shows some carbon dioxide noise between about 2400 to 2250 cm-1. Do you know whether a purge gas was used during the analysis? Also, did the analytical software give a qualitative match (in percent) to the two library spectra?
Ed Hare PhD says:
Thanks for your note. We did not use purge gas during the analysis. The library matches were ~86%. Do you work with FTIR? Thanks!