Microfiltration membranes functionalized with multiple styrenic homopolymer and block copolymer grafts

Abstract

The pores of microfiltration polyethersulfone membranes have been functionalized with homopolymer and block copolymer grafts through sequential cationic polymerization of styrene and substituted styrene monomers, namely 4-chloromethylstyrene and 4-ethoxystyrene.1 H NMR characterization confirmed successful incorporation of polymeric grafts at different stages of functionalization. The functionalized membrane showed a 90% decrease in membrane permeability compared to the raw membrane indicating the presence of polymeric chains in the membrane flow path. Functionalized membranes have as many as 125 repeat units per chain equating to an ion-exchange capacity (IEC) of 4.9 meq/g, representing 92% of the theoretical IEC of an ion-exchange resin. A pseudo-first-order kinetic equation correlated well (R 2 $ 0.99) with the experimental kinetic data of formation of polymeric grafts.Polymer growth studies showed that at lower initiator surface density (initiator contact time <135 min), graft length and IEC were impacted by monomer feed concentration and initiator contact time.

Sustainable Membranes and its Applications

“…The microfiltration membranes use the principle of physical separation to reject particles with sizes higher than the range between 0.1 to 10 µm. Compared to the other kinds, the microfiltration membrane presents more open pores and consequently lower operating pressure than the other classifications [3,31,59,60,74]. The separation of solutes in the ultrafiltration membrane occurs by the pore size difference.…”