M.J. Martínez-Morlanes, A. Terriza, F. Yubero, J.A. Puértolas
Polymer Testing, 31 (2012) 841–847
doi: 10.1016/j.polymertesting.2012.06.005

Colour analysis appears to be a robust technique for characterizing vitamin E doping and gamma irradiation of medical grade polyethylene samples. The analysis procedure described in this paper is of great interest because it can easily distinguish between polyethylene samples with differences in vitamin E (α-tocopherol) doping of about 0.1 wt% and gamma irradiation doses of 30 kGy. It is found that the colour differences (with respect to untreated samples) induced by gamma irradiation and/or vitamin E doping add-up linearly. This method for detecting the presence of vitamin E is fast, simple and non-destructive.