Working group of polymer membranes materials

Head: Zdeňka Sedláková, PhD
(phone +420-296 809 252, e-mail sedlakova@imc.cas.cz)

Research

Synthesis of polymers with specific groups and economically feasible blending are the methods for obtaining materials with required parameters.

• New polymers with a narrow molecular weight distribution and well-defined polymer chain length are synthesized using a nitroxide-mediated quasiliving radical polymerization. Using the nitroxide-mediated polymerization technique, copolymers containing styrene and acrylonitrile or diethyl fumarate units were synthesized. The copolymers are employed as components of supra­molecular polymer systems. Ionised networks exhibiting first-order phase transition as a function of temperature and NaCl concentration were prepared by radical copolymerization of N-isopropyl-methacrylamide, sodium methacrylate and N,N´-methylenebisacrylamide, in water.
• New bifunctional liquid crystal (LC) polyesters with end nitroxyl radicals are synthesized from various alkane-l,w-diylbis(4-hydroxybenzoate)s and 4,4´-(pentanedioyldioxy)di­benzoic acid. Nitroxyl macroradicals were used in the living radical polymerization of styrene as efficient chain terminators to provide a peculiar chain propagation reaction. The produced copolymers had a block structure of the polystyrene - LC copolyester - polystyrene type. The phase behaviour of the synthesized copolymers was characterized.
• Thermotropic polyurethanes were synthesized starting from three commercial diisocyanates of various flexibility and diols based on diethanolamine derivatives with mesogenic groups in side chain at a stoichiometric ratio of reactive isocyanate and hydroxy groups. Polymers were characterized by dynamic mechanical spectroscopy and X-ray scattering, differential scanning calorimetry and polarizing microscopy. These polymers exhibiting photochromic properties based on cis-trans isomerization were used for the preparation of photosensitive polymers.
• Microporous hybrid membranes based on chitin/chitosan and polyhedral oligomeric silsesquioxanes, which control the membrane porous structure on nanoscale, were prepared and tested in separation of amino acids. Macroporous hybrid membranes prepared by consecutive modification of highly porous glass microfibre filters with sinales, POSS, chitin(chitosan) and chelating agents are under study in relation to the purification of microbial chitinases and monoclonal antibodies from biological media by pseudoaffinity and immobilized metal ion affinity membrane chromatography.