Swift heavy ion irradiation effects on carbonyl and transvinylene groups in high and low density polyethylene

DEL GROSSO, M.F.; CHAPPA, V.C.; ARBEITMAN, C.R.; GARCÍA BERMÚDEZ, G.

Buenos Aires, Argentina

Otro; At the Frontiers of Condensed Matter IV: Current trends and novel materials; 2008

Polyethylene is the most widely used polymer and several desirable application properties can be obtained by choosing one of a large variety of its grades. Some works have investigated the local transformations induced by ion-beam irradiation and it has been found that irradiation in polyethylene produces crosslinking, trans-vinylene, end-vynil, vinylidine and carbonyl groups. In previous works we have studied physico-chemical changes in ultra high molecular weight polyethylene (UHMWPE) due to swift heavy ion irradiation. Fourier Transform Infrared Spectroscopy (FTIR) analysis of the irradiated samples showed that, with different ions, the absorbance of the C=C stretching vibration from trans-vinylene groups containing hydroperoxides presents a maximum at certain ion fluence that is correlated with the electronic stopping power. In other work we found that the decreasing part of the absorbance curve after the maximum is not related to the overall destruction of the polymer that occur at higher fluences. Our purpose was to study the creation and destruction of two functional groups and its relation with material density and ion energy. To this end, we have studied the effects of swift heavy ion irradiation on the physico-chemical modifications of high and low density polyethylene (HDPE and LDPE) irradiated with 47 MeV Li, 12 MeV C and 6.7 MeV He as a function of fluence. From the FTIR spectra we analysed the modification on trans-vinylene and carbonyl groups with fluence. Creation and damage cross sections for these groups were compared for three different PE densities.