Synergistic effect of welding electrospun fibers and MWCNT reinforcement on strength enhancement of PAN–PVC non-woven mats for water filtration

Abstract

© 2018 Elsevier Ltd Typical electrospun polymer mats exhibit poor mechanical properties, undesirable for pressure-driven water filtration. Herein, strength enhancement of polyacrylonitrile–poly(vinyl chloride) (PAN–PVC) electrospun mats is demonstrated with a synergistic approach, using solvent vapor-induced welding of the polymer fibers at their cross points and reinforcement of the fibers by unfunctionalized multi-walled carbon nanotubes (MWCNTs). Tensile strength and Young's modulus of the as-spun PAN–PVC mats are increased by 127% and 175% respectively via welding effects, and are further enhanced to 205% and 314% increments respectively, using 1 wt% MWCNTs. The post-treated composite mats achieve over four-fold the modulus predicted by the modified Halpin–Tsai model. With a slight total reduction in pure water flux (8%), water permeability is not greatly suppressed by welding the polymer fibers or by the presence of MWCNTs in the fibers. The two strength-enhancing strategies also allow recyclability of the post-treated composite mats with high particulate (25 nm–5 μm) filtration efficiency of nearly 100% and good antifouling performance (flux recovery of >93%) throughout the 10 tested filtration cycles.