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Nekatere kemijske modifikacije površine fazno inverznih membran iz polisulfona : magistrsko delo
Kukovičič, Irena
Asymmetric porous membranes were prepared from polysuflone by a wet-phase inversion procedure. The membranes were characterized by measuring the turbidity, the membrane thickness and the pure water ...flux through the membrane. Results show high reproducibility of laboratory prepared polysuflone membranes by a wet phase inversion. 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 mambrane surface was modified by the series of Friedel-Crafts electrophilic substitutions of aromatic rings in the polysuflone molecules. As a reagent 1- chlorodecane or propylene oxide dissolved in hexane and A1C13 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 by sulfiric (VI) acid water solution; in this way negative charges were introduced at the membrane surface. The membranes, unmodified and chemicallly modified, were characterized by measuring the membrane thickness, the deionized water flux through the membrane, the zeta potential and by scanning electron microscopy. The specific chemical modifications of the membrane surface affect the water flux and zeta potential 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 -(CH2)9-CH3 groups and reaction with propylene oxide gave a hydrophilic surface with polar group -CH(CH3)-CH2-OH. The surface of sulfonized polysuflone membranes contained ionizable (-SO3H) functional groups.
Type of material - master's thesis
Publication and manufacture - Maribor : [I. Kukovičič], 2000
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