Unipolar Corona Discharge Effect on Filtering Capacity of Polypropylene Non-Woven Fabrics

Resumo

The electret and filtering properties of polypropylene non-woven fabrics of various grades were investigated. It was found that the electret characteristics of the non-woven fabrics depended directly on their structural parameters, i.e., the greater the surface density of the material was, the greater its potential surface, effective surface charge density, and electric-field strength were. It was shown that the air permeability and filtering capacity decreased as the surface density of the polypropylene fabrics increased. The time to filter liquid perfumes increased for the electrets due to the generation of polarization charge as an energy barrier that was overcome by expending the driving force for spreading the liquid over the fiber surface and the increased dynamic viscosity of the liquids in the electric field of the corona electret. The filtrate obtained using electret fabrics was much purer than the control.