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Izpis gradiva

Naslov:Vpliv strukture in zamreženja poli(hema) na vodno absorptivne lastnosti : diplomsko delo univerzitetnega študijskega programa I. stopnje
Avtorji:Ćeranić, Martin (Avtor)
Krajnc, Peter (Mentor) Več o mentorju... Novo okno
Paljevac, Muzafera (Komentor)
Datoteke:.pdf UN_Ceranic_Martin_2019.pdf (3,48 MB)
 
Jezik:Slovenski jezik
Vrsta gradiva:Diplomsko delo/naloga (mb11)
Tipologija:2.11 - Diplomsko delo
Organizacija:FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Opis:V okviru diplomske naloge smo sintetizirali porozni hidrogel poli(2-hidroksietil metakrilat), ki lahko nase veže vodo. Poroznost polimernih materialov lahko dosegamo z uporabo različnih tehnik. S polimerizacijo kontinuirne faze emulzij z visokim deležem notranje faze (HIP emulzije) smo sintetizirali porozne polimere. Pri tem smo kot monomer uporabili 2-hidroksietil metakrilat, ki smo ga zamrežili z N,N´-metilenbisakrilamidom oziroma s trimetilpropan triakrilatom. HIP emulzijo smo stabilizirali s surfaktantom Pluronic F68, polimerizacijo pa smo iniciirali z iniciatorjem amonijevim persulfatom in redoks iniciatorjem N,N,N´,N´-tetrametiletilendiaminom. HIP emulzija je bila tipa olje v vodi, kjer smo kot oljno (notranjo) fazo uporabili topilo cikloheksan. Delež notranje faze, ki tvori pore v tako sintetiziranem materialu (poliHIPE materialu), je bil približno 92,6 vol % glede na volumen emulzije, stopnjo zamreženosti pa smo variirali med 0,5 mol% in 20 mol%. Poli(2-hidroksietil metakrilatne) materiale smo čistili s 24-urno kontinuirno ekstrakcijo v Soxhletovem aparatu, kjer smo kot topilo uporabili 2-propanol. Poli(2-hidroksietil metakrilatne) materiale smo okarakterizirali z različnimi metodami. Kemijsko sestavo smo potrdili s FTIR spektroskopijo, morfologijo smo preverjali z vrstičnim elektronskim mikroskopom, specifično površino smo izmerili s porozimetrom in celokupno gostoto s He piknometrom. Za določevanje absorptivnih lastnosti materialov smo uporabili vodo. S FTIR spektroskopijo smo potrdili kemijsko sestavo polimerov, saj smo v vseh primerih dokazali vključenost uporabljenih monomerov v polimerno verigo. Nekateri polimeri so imeli tipično poliHIPE morfologijo, ki vsebuje primarne pore povezane z manjšimi sekundarnimi porami. Nekateri pa te strukture niso imeli. To so bili tisti polimeri, ki so se med procesom sušenja močno skrčili in se jim je struktura porušila. Ta pojav smo zasledili pri materialih s stopnjo zamreženja pod 5 mol%. Specifična površina sintetiziranih polimerov ni bila visoka in je znašala za porozne materiale med 2 m2/g in 10 m2/g in za materiale s porušeno strukturo med 0,003 m2/g in 0,018 m2/g. Z absorptivnimi testi smo ugotovili, da na hitrost absorpcije vpliva več dejavnikov. Predvsem so tukaj stopnja zamreženosti ter izbira monomera in zamreževala. Hitrost absorpcije je pri višji stopnji zamreženosti večja kot pri nižji stopnji zamreženosti. Sama izbira monomera in zamreževala pa vpliva na kemijsko sestavo emulzije, slednja lahko zelo vpliva na absorbtivne lastnosti, saj je absorpcija vode povezana tudi s številom hidrofilnih delov v molekuli oz. v samem materialu.
Ključne besede:polimeri, poliHIPE, HEMA, zamreženje, absorpcija vode
Leto izida:2019
Kraj izvedbe:Maribor
Založnik:[M. Ćeranić]
Št. strani:X, 39 str.
Izvor:Maribor
UDK:66.095.26(043.2)
COBISS_ID:22677526 Povezava se odpre v novem oknu
NUK URN:URN:SI:UM:DK:MAUED2LI
Licenca:CC BY-NC-ND 4.0
To delo je dosegljivo pod licenco Creative Commons Priznanje avtorstva-Nekomercialno-Brez predelav 4.0 Mednarodna
Število ogledov:89
Število prenosov:25
Metapodatki:XML RDF-CHPDL DC-XML DC-RDF
Področja:KTFMB - FKKT
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Sekundarni jezik

Jezik:Angleški jezik
Naslov:Influence of structure and crosslinking degree of poly(hema) on water absorption characteristics
Opis:In the course of writing our Diploma assignment we synthesized porous hydrogel poly(2-Hydroxyethyl methacrylate), which has the ability to absorb water. Porosity of polymeric materials can be achieved by usage of different techniques. With polymerization of continuous phase of emulsions containing a high percentage of the internal phase (HIP emulsion), we managed to synthesize porous polymers. As a monomer we used 2-Hydroxyethyl methacrylate, which was crosslinked with N,N'-Methylenebisacrylamide, or Trimethylolpropane triacrylate. HIP emulsion was stabilized with surfactant Pluronic F68 and polymerization was injected with initiator Ammonium persulfate and redox initiator N,N,N′,N′-Tetramethylethylenediamine. HIP emulsion was oil-in-water type of emulsion, and as an oil (internal) phase we used a solvent Cyclohexane. The percent of the internal phase, which produces pores in the synthesized material (polyHIPE material), was around 92.6 vol% according to the volume of the emulsion. The level of crosslinking varied between 0.5 mol% and 20 mol%. Poly(2-Hydroxyethyl methacrylate) materials were cleaned by 24-hour continuous extraction in Soxhlet extractor, where we used 2-propanol as a solvent. Poly(2-Hydroxyethyl methacrylate) materials were characterized with various methods. Chemical structure was confirmed by FTIR spectroscopy; morphology was tested by a scanning electron microscope. Specific surface area was measured with a porosity meter and total density by a Helium pycnometer. Water was used to determine the absorptive quality of the materials. By FTIR spectroscopy we confirmed the chemical structure of the polymers, because we managed to prove the participation of used monomers in polymer chain in every instance. Some polymers had a typical polyHIPE morphology, which contains primary pores connected with smaller secondary pores. However, some of the polymers did not have the aforementioned structure. Those polymers shrunk heavily during the process of drying and their structure collapsed. This phenomenon was discovered in materials with crosslinking level of 5 mol% or less. Specific surface area of synthesized polymers was small and ranged between 2 m2/g in 10 m2/g for porous materials and 0,003 m2/g in 0,018 m2/g for materials with collapsed structure. With absorption tests we found out that there are multiple factors to absorption speed. Crosslinking level is one of the main factors, as is the choice of a monomer and a crosslinker. The speed of absorption is faster at the higher level of crosslinking. The choice of a monomer and a crosslinker has an influence on the chemical structure of emulsion, which can heavily affect the absorption characteristics, because the absorption of water is also connected to the number of hydrophilic parts of a molecule or in the material itself.
Ključne besede:polymers, polyHIPE, HEMA, crosslinking, absorption of water


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