Fourier transformed infrared spectrophotometry of gamma irradiated polyethylene

Full text: Polyethylene is a material usually radio processed in sterilization of medical devices or packages and also in radiation crosslinking of thermo resistant products such as tubes, pipes, cables or thermo shrinkable film and tubes. When monitoring the radiation process it its useful to use a material similar to the one under processing. That is the reason for which many authors have examined the use of polyethylene as dosimeter, utilizing properties that show the effect of radiation, such as gel fraction or elongation at break. Infrared absorbance due to trans-vinylene unsaturation has been employed for dosimetry in electron beam irradiation. In the present work we compare a commercial polyethylene of local origin extruded in our laboratory to an imported polyethylene used as dosimeter for electron accelerators. We used Fourier Transformed Infrared spectrophotometry (FTIR) to measure the absorbance of the trans-vinylene group of samples gamma irradiated within the range of doses from 0 to 150 kGy. The stability along the time of the response given by both materials was also considered, up to five months after irradiation.The results show that the local polyethylene gives a response that is comparable to the reference material; both can be considered for the use as dosimeter in irradiation with gamma radiation. Their stability along the elapsed time was excellent