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1.
Chemical modification and characterization of the surface of polysulfone membranes
Irena Kukovičič, Robert Šoster, Milan Brumen, Volker Ribitsch, D. Wiegel, K. Arnold, Črtomir Stropnik, 2000, original scientific article

Abstract: Asymmetric porous membranes were prepared from polysulfone by a wet-phase separation procedure. Different chemical modifications were applied to the upper membrane surface, i.e. the surface which was exposed to interaction with nonsolvent (water) in the coagulation bath during the membrane formation. The membrane surface was modified by the series of Friedel-Crafts electrophilic substitutions of aromatic rings in the polysulfone molecules. As a reagent 1-chlorodecane or propylene oxide dissolved in hexane and $AlCl_3$ as a catalyst were used. In the former case a hydrophobic and in the latter one a hydrophilic coating was achieved, respectively. The membrane surface was also modified by sulfonization with sulfuric (VI) acid water solution; in this way negative charges were introduced at the membrane surface. The membranes, unmodified and chemically modified, were characterized by measuring the membrane thickness, the deionized water flux through the membrane, the zeta potential and contact angle. The specific chemical modifications of the membrane surface affect the water flux, the zeta potential and contact angle values whereas the membrane thickness remains unchanged. These effects are interpreted in terms of hydrophilicity and hydrophobicity, changes of the membrane surface charge and the thickness of shear layer at the membrane surface, all with respect to the particular modification applied. Reaction with 1-chlorodecane gave a hydrophobic surface by nonpolar $–(CH_2)_9-CH_3$ groups and reaction with propylene oxide gave a hydrophilic surface with polar group $-CH(CH_3)-CH_2-OH$. The surface of sulfonized polysulfone membranes contained ionizable ($-SO_3H$) functional groups.
Keywords: polysulfone, chemical modification, Friedel-Crafts electrophilic substitution, sulfonization, hydrophylicity, hydrophobicity
Published: 17.08.2017; Views: 863; Downloads: 86
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2.
Polimerne membrane za ločevanje krvi; kemijska modifikacija njihove površine
Vesna Lahovnik, Irena Kukovičič, Črtomir Stropnik, 1999, original scientific article

Abstract: V laboratoriju pripravljene membrane iz polisulfona (PSf), celuloznega acetata(CA), poliamida 4,6 (PA4,6), poliamida 6,6 (PA6,6) in kopolimera poli-(akrilonitril-ko-akrilna kislina)(kANAK) smo karakterizirali tako, da smo izmerili njihove debeline ter pretoke za deionizirano vodo in nato z njimi izvedli ločevanje krvi prašičev. Membrane iz PSf smo na površini modificirali s Friedel-Crafts-ovo elektrofilno substitucijo aromatskih delov molekule PSf, pri čemer smo vezali 1-klordekan in propilenoksid. Izvedli smo tudi sulfoniranje z žveplovo kislino. Modificirane membrane smo prav tako karakterizirali z merjenjem debelin, pretokov za deionizirano vodo in določanjem "streaming"-potenciala ter nato z njimi izvedli ločevanje krvi prašičev. S primerjavo lastnosti nemodificiranih in na površini kemično modificiranih membran smo ugotavljali učinke kemijske modifikacije površine na separacijske lastnosti polimernih membran.
Keywords: polimerne membrane, kemijska modifikacija, površina, membrane, ločevanje krvi
Published: 10.07.2015; Views: 1061; Downloads: 41
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