Electret Charge Stability in Meltblown Polypropylene Fibers

In the present work charge storage in meltblown polypropylene (PP) fibers has been investigated by means of thermally stimulated surface potential decay. It has been shown that a surface chemical treatment of fibers or, alternatively, polymer granules prior to extrusion, leads to a significant improvement of the electret charge stability. We attribute this to the formation of new deeper traps in the material resulting from the chemical treatment with the phosphoric acid. The results obtained offer a new approach to improve efficiency and charge stability of meltblown electrostatic filters.