Solution-blown PA6-and PVDF-based nanofibrous composite mats for aerosol filtration

Abstract

Particulate matter (PM), especially with particle diameter below 2.5 mu m (PM2.5), causes serious impacts on human health. Nanofibrous filters are one of the most widely investigated materials for the filtration of PM2.5 and viruses from the air at high efficiency. Recent concerns regarding energy efficiency of air control units dictated that a high-performance air filter should not only provide high filter efficiency, but also low pressure drop and longer operational service. Herein, PA6- and PVDF-based nanofibrous filter media for particle filtration via modified solution-blowing (m-SB) system with two separate nozzles was produced. Depending on the concentration, the average fiber diameters for PA6 and PVDF alternated nearly 70-137 and 122-230 nm, respectively. After optimization of the production parameters for each polymer to obtain less droplet density and high fiber content, the mechanical and filtration performance of the composite filter structures produced by blowing two polymers simultaneously were investigated. According to results, the highest and lowest mechanical performance was obtained from PVDF-20 and PA6-20 samples while the composite nanofibrous sample ( PA/PVDF-5) was exhibited a value between them. However, contrary to expectations, the increased production time (PA/PVDF-10 sample) caused a decrease in the mechanical properties of the composite samples. This could be attributed to the abrasive effect of the twofold amount of air coming to the same point per unit of time on the fibrous mat because of simultaneous usage of two nozzles. On the other hand, the filtration efficiency of PA6/PVDF-10 composite filter mat was found superior with 93% efficiency and 194 Pa pressure drop values. Although this efficiency was very close to the efficiency from PVDF-20 sample, the composite sample was 150% thinner.