SUSPENSION POLYMERISATION OF 2-HYDROXYETHYL METHACRYLATE

V diplomskem delu je prikazana študija vplivov na nabrekanje, poroznost, površino, velikost in porazdelitev velikosti poli(2-hidroksietil metakrilat-ko-N,N\u27-metilenbisakrilamid) zrn. Polimerna zrna iz monomera 2-hidroksietil metakrilata (HEMA) in zamreževala N,N\u27-metilenbisakrilamida (MBAA) smo pripravili z inverzno suspenzijsko polimerizacijo, z inciatorjem amonijevim peroksodisulfatom (APS) in stabilizatorjem etil celulozo. Z namenom, da bi ugotovili vpliv zamreževala in porogenih topil na lastnosti sintetiziranih zrn, smo spreminjali količino zamreževala in vrsto dodanega porogena. Prav tako smo izvedli poskus sinteze zrn brez prisotnosti vode v monomerni fazi. Sintetizirana zrna smo preiskali z optičnim mikroskopom pri 40-kratni povečavi, določili sestavo z infrardečo spektroskopijo in izmerili povprečno specifično površino zrn z N2 adsorpcijsko porozimetrijo z BET metodo. Nabrekanje polimernih zrn z različnim deležem zamreževala smo preverili v vodi, etanolu, diklorometanu, toluenu in dioksanu. Ugotovili smo, da se z zniževanjem deleža zamreževala zvišuje stopnja nabrekanja v topilih. Med testiranimi topili pa so zrna najbolj nabrekala v vodi, sledita etanol in dioksan. Opazili smo, da se v diklorometanu zrna raztopijo. Poskus sinteze zrn v odsotnosti vode v monomerni mešanici se je izkazal za neuspešnega. Dobljena zrna so nepravilnih oblik. Vpliv deleža zamreževala na velikost zrn smo ugotavljali pri 25, 10, in 2 mas% zamreženih zrnih. Spoznali smo, da velikost zrn ni neposredno povezana s stopnjo zamreženosti, saj smo dobili najmanjša zrna pri največji zamreženosti. Delci so bili polidisperzni, saj so bile porazdelitve velikosti široke (vse do 500 µm). Ugotavljali smo vpliv porogenov izopropanola, toluena, tetrahidrofurana in n-heptana na velikost in poroznost zrn, pri najvišji stopnji zamreženosti. V tem primeru smo dosegli manjše velikosti zrn (70-300 µm). Najmanjša zrna smo dobili z izopropanolom, največja pa z n-heptanom. Obstoječa zrna so bila bela in večinoma pravilnih sferičnih oblik. Izmerjena površina in količina por vseh polimernih zrn sta bili izredno majhni. Ugotovili smo, da smo dobili zrna z zelo majhnimi porami ali celo neporozna zrna. Poroznost različno zamreženih zrn se je sicer povečevala z višanjem količine zamreževala. Z nobenim od porogenov nismo dosegli odprte porozne strukture. Rezultati so nakazovali na možnost zaprte poroznosti HEMA/MBAA zrn.The thesis presents the study of influences on swelling, porosity, surface area, size and size distribution of poly(2-hydroxyethyl methacrylate-co-N,N\u27-methylenebisacrylamide) beads. Polymer beads from monomer 2-hydroxyethyl methacrylate (HEMA) and crosslinker N,N\u27-methylenebisacrylamide (MBAA) have been prepared by inverse suspension polymerisation, with ammonium peroxodisulfate (APS) as the initiator and ethyl cellulose as the stabilizer. In order to study the influence of crosslinker and porogenic solvents on properties of polymer beads, the quantity of crosslinker and type of porogen have been varied. We also attempted to synthesize the beads without the presence of water in the monomer phase. Synthesized beads have been characterized with an optical microscope at 40-fold magnification, with infrared spectroscopy and with N2 adsorption porosimetry, where the specific surface area of beads has been determined using BET method. We checked the swelling capacities of differently crosslinked beads in water, ethanol, dichloromethane, toluene and dioxane. It has been noticed that swelling capacity increases with reducing the amount of crosslinker. Among the tested solvents the beads were the most swollen in water, followed by ethanol and dioxane. We found out that our beads dissolve in dichloromethane. We failed at the attempt to synthesize our beads without water in the monomer phase. The obtained product was irregularly shaped. We determined the influence of crosslinker on the bead size in beads with 25, 10 and 2 w% of crosslinker. We have noticed that the bead size does not entirely depend on the degree of crosslinking, because we obtained the smallest beads at the highest crosslinking degree. Particles were polydisperse, as the size distributions were broad (up to 500 µm). We have also been studying the influence of porogens isopropanol, toluene, tetrahydrofuran and heptane on bead size and porosity at the highest crosslinking degree. In this case, smaller bead sizes were obtained (70-300 µm). We gained the smallest beads with isopropanol and the largest with n-heptane. Prepared beads were white and mostly in proper spherical shapes. Measured surface area and volume of pores in polymer beads were very small in all cases. We came to the conclusion that our beads have very small pores or are even nonporous. Otherwise, porosity of variously crosslinked beads was increasing with the amount of crosslinker. We did not achieve an open porous nature with neither of porogenic solvents. Results indicated a possibility of closed porosity of HEMA/MBAA beads