Investigation of beta-irradiation effects on the microstructure of low density polyethylene (LDPE)‎ using (PALT)‎

الملخص EN

Beta-irradiation effects on the microstructure of LDPE samples have been investigated using Positron Annihilation Lifetime Technique (PALT).

These effects on the orthopositronium (o-Ps) Lifetime t3, the free positron annihilation lifetime 2 t, the free-volume hole size (Vh) and the free volume fraction (fh) were measured as functions of Beta irradiation-dose up to a total dose of 30.28 kGy.

The results show that the values of t3, Vh and fh increase gradually with increasing Beta dose up to a total dose of 1.289 kGy, and reach a maximum increment of 17.4 %, 32.8 % and 5.86 %, respectively, while t2 reachs maximum increment of 211.9 % at a total dose of 1.59 kGy.

Above these doses, the values show nonlinear changes up to a maximum dose of 30.28 kGy.

The results are discussed in the view point that Beta - irradiation may induce degradation, cross-linking and increasing of crystallinity in the amorphous regions of LDPE.