Membrane sistema polisulfon/N,N-dimetilacetamid/voda

Polymeric membranes were prepared by the wet-phase separation method from solutions of different contents of polysulfone in N,N-dimethylacetamidesolutions were cast in different thickness before immersion into the pure water coagulation bath. Two main processes take place during the formation of membranes: nucleation and growth of the polymer lean phase with subsequent solidification of the polymer rich phase, and the formation of channels, macrovoids and mega-macrovoids. By the first process a cellular structure is formed whilst the second process connects the cells by opening the space between them. The degree of interconnectedness is an additional factor that affects the pure water flux. By changing the cast solution compositions and/or their cast thickness the interconnectedness of the cells can be controlled.Polimerne membrane smo pripravili z metodo mokre fazne inverzije iz raztopin z različno vsebnostjo polisulfona v N,N-dimetilacetamidu, spreminjali pa smo tudi debelino nanosa raztopine pred potopitvijo v koagulacijsko kopel iz čiste vode. Med formiranjem membrane sta potekala dva osnovna procesa: nukleacija in rast s polimerom revne faze s posledičnim nadaljnjim strjevanjem s polimerom bogate faze ter nastanje kanalov, makrovoidov in mega-makrovoidov. S prvim procesom nastaja celična struktura z izoliranimi in nepovezanimi celicami, medtem ko drugi proces povzroči povezovanje celic z odpiranjem praznega prostora med njimi. Stopnja takšne povezanosti celic je eden od faktorjev, ki določajo pretok čiste vode skozi membrano. S spreminjanjem sestave in/ali debeline nanosa raztopine lahko vplivamo na stopnjo povezanosti celic

Propeties determination of Trypsin, immobilized on the surface of celullosic acetate membrane

V prispevku je opisana metoda kovalentne imobilizacije tripsina na površino asimetrične porozne membrane iz celuloznega acetata. Določene so pretočne lastnosti in debeline membrane pred imobilizacijo encima in po njej, aktivnost tripsina v raztopini in lastnosti tripsina v območju pH od 2 do 12

Solidification of polymer in system polysulfone/N,N-dimethylacetamide/water and its morphologic variety

Preučevali smo mokro fazno inverzijo ternaranega sistema polisulfon/N,N-dimetilacetamid/voda (PSf/DMA/voda) z namenom, poglobiti razumevanje mehanizma nastajanja polimernih asimetričnih poroznih membran. Morfologije presekov membran smo preučevali z vrstično elektronsko mikroskopijo, sam proces fazne inverzije pa smo opazovali z merjenjem motnosti membranotvornega sistema med procesom nastajanja membrane. Spreminjanje vsebnosti polimera v raztopini (PSf/DMA) in debeline njenega nanosa povzroči v procesu mokre fazne inverzije poleg nastanka polimernega lateksa formiranje morfološko različnih membran. Nastanejo membrane s celično, dvozvezno in krogličasto zrnatao morfologijo. Njihov nastanek lahko predstavimo s "potmi sestave" v ternarnem faznem diagramu polimer/topilo/netopilo in pojasnimo z različnimi načini fazne inverzije.Wet phase inversion of a ternary system polysulfone/N,N-dimethylacetamide/water (PSf/DMA/water) was studied with intention to enhance the understanding of the mechanism of polymeric asymmetric porous membranes formation. Membranes cross-sections were investigated with scanning electron microscopy and the phase inversion process was observed by turbidity measurement of membrane forming system during the membrane forming process. Changing of polymer content in a PSf/DMA solution and thickness of cast layer cause the formation of a polymer latex and morphologically different membranes during the process of wet phase inversion. Membranes with cellular, bicontinuous and bead-like morphology are formed. Their formation can be presented in ternary phase diagram polymer/solvent/nonsolvent by "composition paths" and explained by different modes of phase inversion