Optimizacija reakcijskih pogojev za kontrolo poroznosti poli(HEMA-ko-EA) materialov

diplomsko delo univerzitetnega študijskega programa I. stopnje

Azra Osmič (Author), Peter Krajnc (Mentor), Muzafera Paljevac (Co-mentor)

Abstract

V diplomskem delu smo se lotili priprave poroznih polimernih materialov s tehniko sintranja poli(metil metakrilatnih) (PMMA) zrn. Sintrana poli(metil metakrilatna) zrna so nam služila kot nosilci za doseganje poroznosti materiala. Preko nosilcev smo prelili monomerno mešanico in jo polimerizirali, nato pa s čiščenjem v Soxhletovem aparatu odstranili PMMA zrna in dobili porozen material. Najprej smo okarakterizirali zrna z vrstičnim elektronskim mikroskopom in jim določili velikostno porazdelitev. Sledila je temperaturna obdelava oz. sintranje. Da smo si pripravili primerno sintrane nosilce, smo morali najprej določiti optimalne pogoje. To sta čas in temperatura sintranja, pri katerih se zrna najbolje povežejo med seboj in se najmočneje med seboj držijo skupaj. Optimalni čas in temperatura sintranja smo dosegli pri 24 h in 180˚C oz. 5 h in 200°C. V postopek priprave sintranih nosilcev smo vklučili še stresalnik, s katerim smo preprečili nastajanje zračnih žepkov med zrni in na tak način prispevali k bolj homogeni morfologiji končnega materiala. Sintrana PMMA zrna smo uporabili kot nosilce oz. šablone za pripravo poroznih akrilatnih polimerov. Kot monomere smo uporabili 2-hidroksietil metakrilat (HEMA), etilenglikol dimetakrilat (EDGMA), etilakrilat (EA) in glicidil metakrilat (GMA). Izvajali smo dva tipa polimerizacije, polimerizacijo v masi in polimerizacijo kontinuirne faze emulzije z visokim deležem notranje faze. V obeh primerih smo medij prelivali preko sintranih PMMA zrn, samo polimerizacijo pa smo inducirali termično v pečici ali pa smo izvedli fotopolimerizacijo v UV komori. Po polimerizaciji smo vzorce čistili najprej v etilacetatu, ki je iz polimerne matrice odstranil PMMA zrna, nato pa še z etanolom, da smo odstranili morebitne nezreagirane reaktante. Končni produkti so bili v obliki monolitov, ki smo jih še okarakterizirali z vrstičnim elektronskim mikroskopom ter s Fourierjevo transformacijsko infrardečo spektroskopijo. V okviru diplomske naloge smo pripravili material z odprto celično strukturo. V primeru polimerizacije v masi so imeli monoliti v strukturi večje primarne pore, ki so nastale na mestih PMMA zrn, ter manjše povezovalne pore, ki so nastale na stičnih mestih PMMA zrn. V skeletu polimerov por nismo zaznali. V primeru polimerizacije kontinuirne faze emulzije z visokim deležem pa smo poleg primarnih in povezovalnih por zaznali prisotnost por v samem skeletu

Keywords

poli(metil metakrilat);sintranje;porozni polimeri;polimerizacija;polimerni nosilci;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2016
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[A. Osmić]
UDC:	666.3-127(043.2)
COBISS:	20309270
Views:	1546
Downloads:	191
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	OPTIMIZATION OF REACTION CONDITIONS FOR CONTROL OF POROSITY OF POLY(HEMA-ko-EA) MATERIALS
Secondary abstract:	In this dissertation porous poly materials were prepared by sintering poly (methyl methacrylate) (PMMA) beads. The sintered poly (methyl methacrylate) beads served as a template in order to achieve porosity of the material. A monomer mixture was poured over the templates and polymerized; later PMMA beads were removed in the Soxhlet apparatus in order to get porous material. Poly beads were firstly characterized with a scanning electron microscope, their distribution size then determined. A temperature treatment or sintering followed. In order to prepare appropriately sintered templates, optimal conditions had to be achieved. Those are the time and temperature of sintering, when the beads are best bound together and are strongly connected. The optimal time and temperature of sintering was achieved at 24 h and 180˚C or 5 h and 200˚C. A shaker was included in the preparation process of sintered templates in order to prevent the formation of air pockets between beads. This contributed to a more homogeneous morphology of the end material. Sintered PMMA beads were used as a template for preparing porous acrylate polymers. 2-hydroxyenthyl methacrylate (HEMA), ethyleneglycol dimethacrylate (EGDMA), ethyl acrylate (EA) and glycidyl methacrylate (GMA) were used as monomers. 2 types of polymerization were executed: Mass polymerization and emulsion polymerization of a continuous phase with a high proportion of the internal phase. In both cases the medium was poured over the sintered PMMA beads. The polymerization was either thermically induced in the oven or a photopolymerization in a UV chamber was executed. After the polymerization, the samples were cleaned in ethylacetate which removed PMMA beads from the polymer mould, and later in ethanol in order to remove any possible unreacted reactants. The final products came in the shape of monoliths, which were characterized with a scanning electron microscope and the Fourier transform infrared spectroscopy. Within the dissertation preparation, material with an open cell structure was prepared. In the case of the mass polymerization, the monoliths in the structure had larger pores that arose in places of the PMMA beads, and smaller connecting pores that arose in the contact points of the PMMA beads. The polymer framework did not show any pores. In the case of the emulsion polymerization of a continuous phase with a high proportion of the internal phase, primary and connecting pores were discovered, as well as pores in the framework itself.
Secondary keywords:	poly(methyl methacrylate);sintering;porous polymers;polymerization;polymer carrier;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	IX, 41 str.
ID:	9165773