Electret state relaxation of polymer fiber materials

The influence of structure and physical-chemical nature of polymers on electret charge relaxation in fiber polymer materials based on various polymer matrix (polyethylene, polyamide, polypropylene), produced by melt-blown technology, was investigated in this work. It has been established, that increase of electret effect in fiber materials as compared to original polymer films is caused by nonstoichiometrical oxygen-included defects formation in the structure of polymer fibers. It has been found that emergence of nonstoichiometrical defects results in the growth of the glass transition temperature, which is more significant in the case of nonpolar polymers and also essentially influences surface properties of polar polymers. Fiber polymer materials were studied by Thermally stimulated Luminescence (TSL) in the temperature range of 80-300 K which, allowed to reveal general relaxation processes, observed in investigated materials: α-process in the area of the glass transition temperature of polymers, as well as low temperature β-and γ-processes caused by the release of charge carriers from electronic traps in the bulk of polymer fibers. The most probable activation energy value and the effective frequency factor of relaxation processes observed in fiber polymer, were calculated by numerical methods.