Formation of pore‐filled microfiltration membranes using a combination of modified interfacial polymerization and grafting

Abstract

A novel method of fabricating pore‐filled membranes has been developed by coating a hydrophobic polyolefinic microfiltration membrane with polyethylenimine (PEI) to produce a chemically active surface. An evaporative coating technique was used to coat the internal surface of a polyolefinic membrane with PEI in chloroform (CHCl3). The coated PEI was then crosslinked by naphthalene‐1,4‐disulfonyl chloride in carbon tetrachloride (CCl4). The incorporation of the PEI coating changed the properties of the base membrane from hydrophobic to relatively hydrophilic; the nitrogens could be titrated, and the coating could not be washed out. 4,4′‐Azo‐bis(4‐cyanovaleryl chloride), a heat‐sensitive radical source, was incorporated into the coated membrane. The coated membrane, with incorporated azo compound, was heated to 75 °C in the presence of acrylic acid, 4‐(vinylpyridine), or styrene to give the corresponding grafted, pore‐filled membranes. The membranes exhibited hydraulic fluxes and pH valve effects consistent with molecular brushes grafted within the pores of the membranes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 242–250, 2002

Surface Modification by Graft Polymerization

“…metal ion-polymer chelate complex. Childs et al (2002) chemically bound a heat-sensitive radical initiator, 4,4'-azo-bis(4-cyanovaleryl chloride), into polyethylenimine-coated hydrophobic PP or polyethylene (PE) membrane and prepared pore-filled microfiltration (MF) membranes by grafting AAc, 4-(vinylpyridine) (4-VP) or styrene (St) at 75 • C. This method can effectively restrain the homopolymerization. Initiated by ceric ammonium nitrate (Zhang et al, 2003), cellulose membranes were grafted with a zwitterionic vinyl monomer, N -dimethyl-N -methacryloxyethyl-N -(3-sulfopropyl) ammonium (DMMSA), to improve the hemocompatibility.…”

Nanofiltration‐like forward osmosis membranes on in‐situ mussel‐modified polyvinylidene fluoride porous substrate for efficient salt/dye separation

“…On the other hand, the polar functional groups on the in-situ mussel-modified PVDF membrane can improve its hydrophilicity, make the PA layer are firm with the porous substrate and few defects. [25][26][27] As a result, the resultant NF-like TFC FO membrane has high water flux and selectivity for separation salt/dye.…”

“…On one hand, some PDA‐PEI aggregates leach out from the blend membranes during the NIPS process, leading to large pores and water channels. On the other hand, the polar functional groups on the in‐situ mussel‐modified PVDF membrane can improve its hydrophilicity, make the PA layer are firm with the porous substrate and few defects 25–27 . As a result, the resultant NF‐like TFC FO membrane has high water flux and selectivity for separation salt/dye.…”

Pore size modification of macroporous crosslinked poly(dicyclopentadiene)

“…Currently, the latter are a subject of great interest among analytical chemists, as demonstrated by the report at the PITTCON 2002 conference by Stevenson 3. These materials have shown great potential in applications such as membranes, ion exchange, and chromatographic media 4–13. For these applications, as well as for applications such as solid support resins, carriers, catalysts, and adsorbents, surface functionality is required to promote appropriate interactions.…”