An Efficient Ethanol-Vacuum Method for the Decontamination and Restoration of Polypropylene Microfiber Medical Masks & Respirators

Albert I. Nazeeri; Isaac A. Hilburn; Daw-An Wu; Kabir A. Mohammed; D. Yovan Badal; Moses H.W. Chan; Joseph L. Kirschvink

We attribute the degradation of mask performance to the presence of adsorbed moisture that causes the micron scale electrostatic polypropylene fibers to clump together, significantly reducing the effective surface area of the filtering material. In addition, water adsorbed on the surface of the microfibers might interfere with their electrostatic interactions. The vacuum treatment fully dries the mask, allowing the fibers to spring back to their original arrangement, and restores the available surface area so that the electrostatic fibers are effective in capturing the micron and submicron size particles. Because moisture can accumulate in masks as they are used, mask performance might degrade even absent a decontamination treatment. If so, conditioning processes for extending the usable life of masks, even ones that do not involve water, should completely dry the masks in order to counteract any adsorbed water that may have accumulated during extended use.