One-step melt blowing process for PP/PEG micro-nanofiber filters with branch networks

Polyethylene glycol (PEG) was inserted into polypropylene (PP) in one-step melt blowing process to strengthen the filtration quality of the melt-blown nonwovens. The micro-nanofiber nonwovens with branch structure were fabricated by controlling the ratio of PEG in blend and process parameters in melt blowing process. The results showed that nanofibers with the diameter range of less than 800 nm were interspersed among microfibers, which demonstrated the laminated structure in thickness direction and quasi-continuous branch structure in horizontal direction. Furthermore, as the PEG ratio increasing from 0% to 15%, the ratio of fibers with diameter of <800 nm and the fibers with diameter of >1500 nm increased from 37.50% to 231.82%. The filtration efficiency of the nonwovens followed typical behavior for the particles of 0.26 μm at air velocities of 0.05–0.142 m/s. The quality factor displayed an escalating trend with the increase of PEG ratio from 0% to 12% and achieved a maximum value of 0.02614 Pa−1 at the airflow rate of 0.053 m/s. Furthermore, the mechanism of formation of branch networks in nonwovens and its filter efficiency were discussed in detail. This work provides the feasibility of fast preparation of micro-nanofiber nonwovens with branch networks under high effective air filtration.