Thermally stimulated luminescence in LDPE fibers

Low density polyethylene (LDPE) fiber materials, produced by melt-blown technology, were investigated, which are important for the production of electret filters. The paper presents the results of a comparative investigation of the thermally stimulated luminescence irradiated by electron gun in the films and fibers based on LDPE. There are three relaxation processes, which take place in the temperature interval 80-300 K: γ-process in the temperature range 110 K, which is connected with the end and side groups of macromolecules of polymer chain, β-process in the temperature range 150 K, which is connected with the emptying of electronic capture centers due to dipole-group mobility, and α-process in the temperature range 230 K which is connected with the defrosting of segmental mobility due to the phase transition from glass to high elastic state. It is important to point out that all processes observed in fibers and films can be explained at the molecular level of the given polymer structure. At the same time the comparison with the polymer film of the same material some processes in fibers meet some difficulties, which finally leads to an increase of electret stability in fiber materials.