Studying phenomena in high-efficiency filtration systems modified in low-temperature plasma

Research on modifying melt-blown non-wovens in low-temperature plasma involved using four gases - argon, oxygen, nitrogen and air - in various process conditions: gas flow velocity, power supplied to the reactor, the time non-wovens are processed in plasma and pressure in the chamber. The properties of the non-wovens after modification were evaluated: filtration efficiency against liquid particles was evaluated by measuring permeation by paraffin oil mist, filtration efficiency against solid particles was evaluated by measuring permeation by sodium chloride aerosol, changes in surface topography was evaluated with scanning microscopy, changes in the chemical character of the surface of the non-wovens was evaluated with infrared absorption spectrophotometry.The research results regarding the stability of the obtained effects of modifying the surface of PP fibres confirmed that modifying melt-blown non-woven in argon was the best variant in view of an increase of the filtration efficiency and maintaining that value in time. As a result, those non-wovens were used in constructing a model filter. Tests conducted to check compliance with standard EN 143:2000/A1/:2006 that is binding in the EU confirmed that the model filter met the criteria for the highest, 3rd class efficiency for multi-use filters.