Positron Annihilation Lifetime Study of Pure and Doped Polyvinyl Chloride with Al2O3

Positron annihilation lifetime of pure and doped polyvinyl chloride (PVC) with Al2O3 reflect the effect of concentration as well as temperature on free volume. Therefore, variations of the ortho-positronium (o-Ps) lifetime and its intensity have been correlated with changes in the dielectric properties of the pure and doped PVC. The o-Ps lifetime and its intensity show a linear dependence with a discontinuity at 20 % concentration of Al2O3. The size and the fractional of the o-Ps hole volume were estimated from the positron annihilation parameters. Therefore, the temperature dependence of the electrical conductivity and the positron annihilation parameters on pure and doped PVC with 20 % Al2O3 were studied in the range from 20 to 140 degree C. The shift of the glass transition temperature to lower temperature for the 20 % Al2O3 doped PVC might explain the increase in the electrical conductivity with the concentration of the additive