THE INFLUENCE OF CHEMICAL AND MORPHOLOGICAL STRUCTURE OF POROUS POLYMETHACRYLATES ON THE IMMOBILISATION OF BIOLOGICAL MACROMOLECULES

V okviru doktorske disertacije smo preučevali vpliv različnih parametrov na morfološke lastnosti visoko poroznih metakrilatnih polimerov, pripravljenih s polimerizacijo emulzij z visokim deležem notranje faze. Variirali smo vrsto iniciatorja, delež surfaktanta, delež notranje faze, razmerje med monomeri, hitrost in temperaturo mešanja ter s tem velikost por uspeli kontrolirano optimirati od submikronske pa vse do 90µm. Poleg morfologije smo optimirali tudi mehanske lastnosti, ki so pri visoko poroznih materialih zelo pomembne. Najbolj raziskan in uporabljen sistem za poliHIPE materiale je na osnovi stirena, zamrežen z divinilbenzenom in glede na to, da ima poli(metil metakrilat) že v osnovi boljše mehanske lastnosti kot polistiren, smo podobno izboljšanje pričakovali tudi pri samih poliHIPE materialih. V kombinaciji z uporabo namiznega mešala in daljšega časa mešanja, smo pripravili porozen material s hierarhično porazdelitvijo por, kateri ima pri 75 % poroznosti upogibni modul elastičnosti 211 MPa, kar je najvišji E-modul za poliHIPE materiale s primerljivo poroznostjo. V drugem delu smo pripravili porozne polIHIPE materiale na osnovi glicidil metakrilata, zamrežene z etilenglikol dimetakrilatom. Glicidil metakrilat je zanimiv, ker vsebuje za nukleofile reaktivno epoksi skupino, ki je primerna za neposredno funkcionalizacijo. Z variiranjem vrste iniciatorja, deleža surfaktanta, deleža notranje faze, razmerja med monomeroma ter hitrosti in temperature mešanja smo uspešno optimirali morfologijo, ki je bila primerna za nadaljnjo funkcionalizacijo. Žilavost materiala, ki je zelo pomembna v pretočnih sistemih, pa smo zopet uspeli izboljšati z dodatkom metil metakrilata. Pripravili smo tudi nosilce na osnovi glicidil metakrilatnih poliHIPE materialov, na katere smo z nukleofilno adicijo, preko aminskih skupin uspešno imobilizirali encim glukoza oksidaza in nosilec uporabili za modelno reakcijo oksidacije glukoze v glukonsko kislino. Aktivnost pripravljenega nosilca z vezanim encimom smo določali na FIA sistemu in kot rezultat dobili graf površine v odvisnosti od časa v obliki linearne premic, s čimer smo dokazali uspešnost imobilizacije. V zadnjem delu smo pripravljene poliHIPE materiale funkcionalizirali z različnimi tioli in funkcionalne polimere uporabili za vezavo težkih kovin srebra, svinca in kadmija iz vode. Prav tako smo vezavo težkih kovin izvedli z realnim vzorcem kontaminirane vode. Z materialom, funkcionaliziranim s pentaeritrol tetrakis (3-merkaptopropionatom), smo uspeli odstraniti 89,6 % Ag+ ionov ter 48,2 % Pb2+ ionov. Z materialom, funkcionaliziranim z 1,9-nonanditiolom pa smo uspeli odstraniti 82,3 % Ag+ ionov in 8 % Pb2+ ionov. Cd2+ ione smo na površino funkcionalnih poliHIPE materialov uspeli le adsorbirati, vendar so se ti s časom iz materiala sprali. Podobno smo pri vezavi nizkih koncentracij kovinskih ionov iz realnega vzorca, z materialom, funkcionaliziranem s pentaeritrol tetrakis (3-merkaptopropionatom), uspeli odstraniti veliko večino srebrovih ionov, z materialom, funkcionaliziranem z 1,9-nonanditiolom pa večino srebrovih in kadmijevih ionov. Rezultati dokazujejo, da so funkcionalni nosilci primerni predvsem za selektivno odstranjevanje srebrovih ionov iz kontaminirane vode.Influences of various parameters on the morphological properties of highly porous methacrylate polymers, prepared by the polymerisation of high internal phase emulsions, was studied. By varying the type of the initiator, the amount of surfactant, the amount of the internal phase, the monomer ratio, the mixing speed and temperature, the cavity diameter could be controlled and tailored in the range between sub-micron and up to 90μm. In addition, mechanical properties, that are very important in high porous materials, were also optimised. The most studied and used system for PolyHIPE materials is based on styrene, crosslinked with divinylbenzene and based on the fact that neat poly (methyl methacrylate) exhibits better mechanical properties han styrene, the same trend was also expected for poliHIPE materials. The combination of the use of an overhead stirrer and longer mixing time resulted in porous material with hierarchical distribution of pores, which had a flexural modulus of elasticity of 211 MPa at 75% porosity and, which is the highest flexural modulus for PolyHIPE materials of comparable porosity. Further on, porous PolyHIPE materials based on glycidyl methacrylate, crosslinked with ethylene glycol dimethacrylate, were prepared. Glycidyl methacrylate is interesting because it contains reactive epoxy groups, which are suitable for the further functionalization. By varying the type of the initiator, the amount of surfactant, the amount of the internal phase, the monomer ratio and the mixing speed and temperature, the morphology was successfully optimised and thus suitable for further functionalization. The toughness of the material, which is very important in flow-through systems, was again improved with the addition of methyl methacrylate. Hereinafter, enzyme glucose oxidase was successfully immobilised by nucleophil addition via amino groups on glycidyl methacrylate based PolyHIPE supports, which were than used for a model reaction of oxidation of glucose into gluconic acid. The activity of the prepared support with immobilisesd enzyme was determined with FIA system. As a result, a graph of the surface as a function of time was obtained in the form of linear line, which proved the effectiveness of immobilisation. In the last part, prepared PolyHIPE materials were functionalized with different thiols and used to bind for the removal of silver, lead and cadmium ions from water. The removal of heavy metal ions was also carried on real sample of contaminated water. With material, functionalized with pentaerythritol tetrakis(3-mercaptopropionate), we were able to remove 89.6% of Ag+ ions, and 48.2% of Pb2+ ions and with material, functionalized with 1,9-nonanedithiol, we were able to remove 82.3% of Ag+ ions and of 8% Pb2+ ions. At the beginning, Cd2+ ions were adsorbed on the surface of functional polyHIPE materials but with time they were washed off the material. The trend with the removal of low concentrations of metal ions from the real sample was simillar. With the material, functionalized with pentaerythritol tetrakis(3-mercaptopropionate), a large majority of the silver ions was removed and with the material, functionalized with 1,9-nonanedithiol most of the silver and cadmium ions were removed. Nevertheless, we can say that the functionalized poliHIPE supports are suitable for the selective removal of silver ions from contaminated water