Preparation and Characterization of magnetic PLA/Fe3O4-g-PLLA composite melt blown nonwoven fabric for air filtration

Abstract

A kind of magnetic poly (lactic acid) (PLA) melt blown nonwoven fabric (MB) was fabricated by the introduction of ferroferric oxide (Fe3O4) nanoparticles to improve its air filtration performances. In view of the poor compatibility of two components, the poly (L-lactic acid) (PLLA) molecular chains was firstly grafted onto the Fe3O4 nanoparticles surface via the ring opening polymerization (ROP). Then, PLA/Fe3O4-g-PLLA composite masterbatches with different mass ratios were prepared by melt-blending method and processed into the corresponding composite MB. The structures and performances of PLA/Fe3O4-g-PLLA composite masterbatches and their MB were investigated. The results showed that the addition of Fe3O4-g-PLLA nanohybrids hardly influenced the glass transition, cold crystallization and melting behaviors of the composite masterbatches. Though the melt fluidity of the composite masterbatches reduced with the Fe3O4-g-PLLA content increasing, the composite masterbatches still could present the appropriate processability in the range of 210°C to 230°C. Fe3O4-g-PLLA could be uniformly dispersed in PLA matrix and had a good interfacial compatibility with the matrix. Compared with pure PLA MB, the fiber surface of the composite MB became slightly rough, the pore size and distribution of the fiber web increased. The addition of Fe3O4-g-PLLA endowed PLA MB with magnetism. With the increasing of Fe3O4-g-PLLA content, the air permeability of the composite MB was improved and their filtration resistance obviously reduced. When the content of Fe3O4-g-PLLA was 0.5 wt%, the filtration efficiency of the composite MB reached the maximum. Moreover, the composite MB have higher longitudinal tensile strength and elongation at break than those of pure PLA MB.