Far-infrared Spectroscopic Identification of Seven Kinds of Antioxidants in Polymeric Insulation

Quantum chemical verification of identification of three phenol-type antioxidants by far-infrared absorption spectroscopy

“…The present research clearly demonstrates that major absorption peaks in the FT-FIR spectra we showed in our previous papers [22][23][24][25] are due to vibrations of the entire molecular structure, at least as far as the spectra of the three phenol-type antioxidants are concerned. This finding is important not only scientifically but also industrially.…”

“…From such a viewpoint, we obtained FT-FIR and THz spectra for more than seven kinds of antioxidants and reported that the two spectroscopic analyses have a potential ability to identify antioxidants even if they have similar structures. [21][22][23][24][25] Furthermore, we have demonstrated that a chemometric analysis can make the identification more reliably even if we do not know a reference spectrum of a pristine polymer with no anitioxidants. 24,25) However, we have not confirmed that the spectra we had obtained truly reflect the molecular structure of each antioxidant.…”

“…As reported in our previous papers, [21][22][23][24][25] a low density polyethylene (LDPE) sheet 2.0 mm thick containing uniformly mixed antioxidant with a weight content of 5.0 wt% was used for this research. First, FT-MIR spectra at wave numbers from 400 to 4000 cm −1 were measured for the sheets containing antioxidants, and the absorption coefficient (α) was calculated as a function of wave number for all the sheets.…”