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Gas‐phase photoinduced graft polymerization of acrylic acid onto polyacrylonitrile ultrafiltration membranes
Author(s) -
Ulbricht Mathias,
Oechel Annett,
Lehmann Claudia,
Tomaschewski Georg,
Hicke HansGeorg
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070551301
Subject(s) - polyacrylonitrile , membrane , polymer chemistry , photoinitiator , polymerization , surface modification , polymer , materials science , ultrafiltration (renal) , acrylic acid , monomer , chemical engineering , permeation , chemistry , chromatography , composite material , biochemistry , engineering
Heterogeneous surface modification of polyacrylonitrile (PAN) ultrafiltration (UF) membranes is realized with UV irradiation‐initiated graft polymerization of acrylic acid (AA) from the gas phase onto photoinitiator (benzophenone, BP)‐coated samples. In the absence of monomer, PAN functionalization by ketyl radicals dominates after UV excitation of sorbed BP. With AA, graft and total polymer yield increase with BP loading and UV irradiation time. Average molecular weight and distribution of PAA homopolymer—formed in parallel during graft polymerization—are analyzed with gel permeation chromatography. Morphology of PAN‐ gr ‐AA UF membranes is checked with scanning electron micrographs (SEMs) and atomic force microscopy. Chemical changes are characterized with FTIR‐ATR spectroscopy and SEM/EDX analyses, indicating a pronounced surface selctivity of the graft polymer modification (localized in the upper 5‐μm membrane thickness). The amount of grafted PAA systematically reduces membrane permeability and increases dextrane retention, as verified in UF experiments. Photo graft polymer modificationof UF membranes will be applied to adjust membrane performance by controlling surface hydrophilicity and permeability using other monomers and/or further graft polymer functionalization. © 1995 John Wiley & Sons, Inc.