Thermally Stimulated Current in Elongated Low Density Polyethylene Film

Three thermally stimulated current peaks were found at 35°C, 45°C and 60°C in low density polyethylene film above room temperature. Further experiments on elongated samples showed that the second peak at 45°C could be considered to increase for draw ratios up to 200%, but that it decreased for draw ratios over 200%. Neither the peak temperatures of the three peaks, nor the heights of the peaks at 35°C and 60°C, seem to be affected by the elongation. Because the peak temperatures of the peaks at 35°C and 45°C come closer to each other with descending warming rate, some interaction exists between their corresponding trapping sites. The increase and decrease in the peak at 45°C may be explained by the melt-recrystallization mechanism, which has been suggested by data on X-ray long spacing measurements, in high density polyethylene films elongated at room temperature.