HEAVY-IONS TRACK STRUCTURE IN A PETP

Differential scanning calorimetry (DSC) studies of poly(ethylenetherep htalate) (PETP) film irradiated with high energy heavy ions at high io ns fluencies are reported. Thin Mylar and Hostaphan PETP films (23 mu m or 19 mu m thick) were irradiated with Ar, Dy and Pb ions of the fol lowing energies and ions fluencies: Ar - 5.5 MeV/amu, 6 X 10(11) ions/ cm(2); Dy - 13 MeV/amu, 5 X 10(10) ions/cm(2) and ca. 10(11) ions/cm(2 ); Pb - 11.4 MeV/amu, 10(10) ions/cm(2). DSC measurements were perform ed in nitrogen during heating-cooling-heating cycles at heating-coolin g-heating rates of: 10-10-10 degrees/min and 2-20-2 degrees/min. Signi ficant differences between pristine and the irradiated material were o bserved during melting and recrystallization processes occurring on pr imary heating, cooling and secondary heating. They have been attribute d to film amorphization during heavy ion irradiation as a result of de gradation and crosslinking, confirmed by gel permeation chromatography (GPC). The decrease in crystallinity and disappearance of long range order in the highly irradiated samples have been confirmed by wide and small angle X-ray scattering (WAXS, SAXS) results and density measure ments. This can also be concluded on the basis of IR spectroscopy patt erns. The DSC method can be applied in studies of structural changes o ccurring in thin polymer films after heavy ion irradiation.