Gas‐phase photoinduced graft polymerization of acrylic acid onto polyacrylonitrile ultrafiltration membranes

Abstract

SYNOPSISHeterogeneous 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 B P 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 selectivity of the graft polymer modification (localized in the upper 5-pm membrane thickness). The amount of grafted PAA systematically reduces membrane permeability and increases dextrane retention, as verified in UF experiments. Photo graft polymer modification of U F membranes will be applied to adjust membrane performance by controlling surface hydrophilicity and permeability using other monomers and/or further graft polymer functionalization. 0 1995

Single-side hydrolysis of hollow fiber polyacrylonitrile membrane by an interfacial hydrolysis of a solvent-impregnated membrane

“…Therefore, PAN has been successfully applied as one of the fascinating membrane materials. In recent years, one of the most important applications is that the porous PAN UF membranes were used as the supports for nanofiltration and pervaporation composite membranes [3][4][5][6][7][8][9][10][11][12][13][14]. This is because PAN membrane surface is relatively active and in turn the property is much easier to be modified.…”

“…This is because PAN membrane surface is relatively active and in turn the property is much easier to be modified. The modifications of PAN UF membranes usually include plasma treatment [3], plasma-initiated graft polymerization [4][5][6], photo-induced grafting [7] and hydrolysis [8][9][10][11][12][13][14]. Among these methods, alkaline hydrolysis is one of the most important and most frequently used methods for PAN-based membranes, due to the convenience and favorableness for further modification.…”

“…Among these methods, alkaline hydrolysis is one of the most important and most frequently used methods for PAN-based membranes, due to the convenience and favorableness for further modification. The hydrolysis with alkaline solution is based on the conversion of -CN groups on the PAN membrane surface firstly into -CONH 2 , then into -COO − groups [1,7,9,10]. A number of studies have reported the PAN-based composite membranes.…”

Polyacrylonitrile Fiber as Matrix for Immunodiagnostics

“…There is a lot of interest in modifying PAN by changing its surface structure by plasma and photo-induced graft co-polymerization [Deng et al, 2003;Hartwig, et al, 1994;Ulbricht, et al, 1995;Zhao, et al, 2005;Zhao, et al, 2004] enzymatic [E. Battistel, et al, 2001] and chemical modifications including hydrolysis and reduction of PAN fibers. Haiquing Liu et al [Liu & Hsieh, 2006 48] have hydrolysed PAN nanofibers to improve its water absorbing capacity.…”

Plasma based surface modification of Poly (dimethylsiloxane) electrospun membrane proper for Organ On a Chip applications

“…Furthermore, other similar protocols as well as irradiation methods, known as photochemical modifications, have been used [21][22][23]. Zhang et al [24] used UV radiation to change the hydrophobicity of the poly (vinylidene fluoride) (PVF) membrane.…”