Online prediction of the filtration performance of polypropylene melt blown nonwovens by blue-colored glow

摘要

In recently years, fine particulate matter (PM) pollution has drawn worldwide attention due to its serious threat to public health, visibility, climate, and ecosystems. The electret filter that can significantly improve the filtration efficiency without increasing the pressure drop has been widely used to for PM filtration. However, there were still some blind spots in the corona charging process, such as the interaction effects between the charging factors on the electret performances and the electric spark phenomenon during charging, which generate challenges for further improving the electret performance. Herein, we report an inconspicuous charging phenomenon that a blue-colored glow was observed during corona charging process. We named it as "Waterfall glow", because a lot of charges appear to flow. The relationship between the blue-colored glow and the filtration efficiency was investigated. The results showed that the filtration performance of the electret melt blown was positively correlated to the intensity of blue-colored glow. The phenomenon enables us to online predict the filtration performance of the electret material in the actual production. (C) 2017 Wiley Periodicals, Inc.