Abstract: Filter media containing an impregnant obtained by pre-reacting an amine functional material with a transition metal to form an amine-metal coordination complex. The complexed amine is much more compatible with amine sensitive co-impregnants or amine sensitive substrates. Additionally, even though the amine is complexed, the impregnant retains high activity for the removal of cyano-containing vapors and other contaminants for which amines have a filtering efficacy. Advantageously, therefore, the filter media may be used to remove cyano-containing vapors or other amine-targeted contaminants from air and other harmful gases in the presence of metal-based catalysts (such as those catalysts comprising platinum, gold or other active transition metals) without the undesirable effect of unduly inhibiting or poisoning the metal-based catalysts.

Abstract: An electret article that includes a polymeric material that has electric charge imparted thereto, that has one or more heteroatoms, that has a fluorosaturation ratio of less than 200, and that has an atomic percent fluorine of greater than about 40%. The inventive electret article is resistant to charge degradation upon exposure to high temperatures for prolonged time periods.

Abstract: A filter that includes a first electret filter layer through which an airstream first passes before encountering a second electret filter layer. The first filter layer exhibits nondecreasing removal efficiency and removes a majority of a challenge aerosol; whereas the second layer exhibits decreasing removal efficiency and has an initial quality factor greater than the first layer. Together, the first and second electret filter layers can provide a filter that exhibits a nondecreasing removal efficiency and a relatively low pressure-drop. The filter can provide nondecreasing removal efficiency and reduced pressure drop even though the second electret filter layer exhibits decreasing removal efficiency in contrast to the desired nondecreasing removal efficiency for the filter as a whole.