29 KB831 KB23 KB200020242010Drev, DarkoPanjan, Jožeštevilka:2letnik:44str. 51-57ISSN:1580-2949COBISSID:4903009URN:URN:NBN:SI:doc-C498PANSslInštitut za kovinske materiale in tehnologijeMateriali in tehnologijefiltracijahidrofobnostmembranepolitetrafluoroetilenNekaj možnih postopkov izdelave hidrofobnih in oleofobnih polimernih membran ter njihova uporaba| Hydrophobic and olephobic membrane usage and production processes|Hydrophobic and oleophobic membrane properties are very desirable for certain filtration process, giving them an advantage over other materials. A polytetrafluoroethylene (PTFE) membrane production process is presented, revealing a minimum membrane pore size of approximately 0.01 m. It follows that such membranes are not suitable for very fine filtration uses (ultrafiltration, reverse osmosis). In addition to PTFE, polysiloxanes are also marked by enhanced hydrophobic and oleophobic properties. However, polysiloxane membranes suffer from severe production process limitations as their production has thus far not been possible via classical phase inversion processes. Thus, several oleophobic and hydrophobic coatings based on mechanic foams and emulsions have been introduced as a crude replacement for expensive PTFE membranes. These require the introduction of a suitable hydrophobic or oleophobic material such as fluorocarbon into the polymer matrix. However, the degree of the resulting membrane opennes and pore size are not comparable to those of PTFE membranes. In this paper, I present a new production process for asymetric polysiloxane membranes that provides the basis of a solution to this problem. This process could allow the creation of very fine asymetric polysiloxane membranes that would have a large comparative advantage to polymers existing todayPri nekaterih vrstah uporabe so zelo zaželene hidrofobne in oleofobne lastnosti membran. To daje takšnim membranam odločilno prednost pred drugimi materiali. Na podlagi prikazanega postopka izdelave PTFE-membran je razvidno, da njihove pore ne morejo biti manjše od pribl. 0,01 m. To pomeni, da tovrstne membrane ne moremo uporabljati pri zelo finih filtracijah (ultrafiltracija, reverzna osmoza). Poleg politetrafluoretilena imajo zelo izražene hidrofobne in oleofobne lastnosti tudi polisiloksani. Tako kot obstajajo omejitve pri izdelavi PTFE-membran, so tudi pri polisiloksanih (silikonih). Polisiloksanskih membran žal ni mogoče izdelati po klasičnem postopku inverzije faz. Kot zelo grobi nadomestki za drage PTFE-membrane so se uveljavili tudi razni oleofobni in hiodrofobni premazi na osnovi mehanskih pen in emulzij. V obeh primerih mora biti v osnovno matrico vgrajen ustrezni hidrofobni in oleofobni material (na primer fluorkarbon). Odprtost strukture in velikost por pri tovrstnih materialih še zdaleč ni primerljiva s PTFE-membranami. V tem članku je opisan nov postopek izdelave asimetričnih polisiloksanskih membran, ki je osnova za rešitev nastalega problema. Na podlagi takšnega postopka bi bilo morda možno izdelati tudi zelo fine asimetrične polisiloksanske membrane, ki bi imele veliko primerjalno prednost pred vsemi drugimi polimernimi materialiTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije