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

We added each of seven different kinds of anti- oxidants to a low-density polyethylene sheet and measured their Fourier-transform mid-infrared (FT-MIR) and FT-far-infrared (FT-FIR) absorption spectra. As a result, it has become clear that each antioxidant in general gives a clear specific FT-FIR spectrum even when the FT-MIR spectrum of the corresponding antioxidant is very similar to the spectra of other antioxidants.

I. Introduction

Various organic polymers are used for electrical insulation purposes in many power devices, apparatus, and cables. Degradation of polymers would sometimes cause malfunctions in such apparatus. Oxidative decomposition is a major cause of such degradation in polymers. In general, many kinds of antioxidants are added to prevent oxidation. The antioxidant added in a polymer is usually not disclosed. In this regard, it is desirable for users to have a tool that can identify the antioxidant in a polymer.