Temperature influence on dielectric properties of PP-SiO2 nanocomposites

The influence of the temperature variation and of the sense of this variation, increasing or decreasing, on the dielectric behavior of polypropylene (PP)-SiO
₂
nanocomposites were studied in this work. The dielectric spectra were recorded in the range 10
^-2
- 10
⁶
Hz in three different modes of temperature variation, between 27 °C and 77 °C. The results show that the relaxation frequency at a given temperature may vary up to four orders of magnitude depending whether that temperature was reached in increasing or decreasing way. Water absorption during temperature variation and chemiluminescence results are discussed in connection with the dielectric behavior.