Influence of annealing treatment on the electrical conductivity of low density polyethylene

The results obtained with films of a low density polyethylene subjected to variations in temperature from ambient to 60 degreesC and in an applied field from low values of around IV mum(-1) to high values (about 50V mum(-1)) are presented. To identify the probable conduction mechanism in such films, a model based on the proposition of Nath and Perlman is investigated which takes into account the effects of space charge and Poole field-assisted detrapping. We observe a relatively good agreement in measurements of current as a function of voltage and temperature. This allows us to evaluate a parameter related to trap characteristics (density, energy level, trap-site separation, etc). Complementary measurements by differential scanning calorimetry show that the structure of the films is modified by temperature variations within the range used to study the conduction mechanism. These structural changes are then correlated with the experimental parameter obtained from Nath's model. (C) 2001 Society of Chemical Industry.