Termodinamske lastnosti sistema polimer/superkritični fluid

diplomsko delo univerzitetnega študijskega programa I. stopnje

Tibor Kuna (Author), Željko Knez (Mentor), Mojca Škerget (Co-mentor)

Abstract

Namen diplomskega dela je preučevanje termodinamskih lasnosti binarnega sistema polietilen glikol/žveplov heksafluorid, primerjava naših eksperimentalnih rezultatov s podobnimi sistemi in postavitev termodinamskega modela za preiskovani plin. Pri preučevanju termodinamskih lastnosti binarnega sistema nas zanima topnost S ter difuzijski koeficient D plina v talini polimera. V ta namen smo vse eksperimente v avtoklavu izvedli izotermno pri 70°C oz. 90°C in v tlačnem razponu od 100 bar do 250 bar. Zatehtano maso polimera smo vstavili v avtoklav, izpostavili različnim tlakom pri določeni temperaturi ter vzorec izpostavljali približno en dan, da se vpostavi ravnotežje. Naslednji dan smo tlak v avtoklavu znižali na atmosferskega in prenesli vijalo iz avtoklava na tehtnico, kjer smo beležili padanje mase zaradi uhajanja plina iz vzorca. Naredili smo tudi primerjavo naših rezultatov za difuzivnost pri 70°C s podobnim binarnim sistemom polietilen glikol/ogljikov dioksid. Za postavitev termodinamskega modela uporabljenega plina žeplov heksafluorid smo v programu Wolfram Mathematica uporabili Peng-Robinsonovo (PR) enačbo stanja. Z modelom smo prikazali gostoto plina kot funkcijo temperature in tlaka. Glavne ugotovitve diplomskega dela so: Topnost je pri obeh temperaturah naraščala s tlakom, medtem ko ima difuzivnost pri obeh temperaturah podoben trend naraščanja do maksimalne vrednosti, kateri je sledil padec vrednosti D z nadaljnim višanjem tlaka. Primerjava vrednosti D s podobnim sistemom je pokazala primerljiv trend med obema, vendar opazno razliko med vrednostmi posameznih sistemov.

Keywords

polietilen glikol;superkritični žveplov heksafluorid;avtoklav;difuzivnost;topnost;

Data

Language:	Slovenian
Year of publishing:	2013
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[T. Kuna]
UDC:	544-971(043.2)
COBISS:	17453334
Views:	1815
Downloads:	178
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	THERMODYNAMIC PROPERTIES OF POLYMER/SUPERCRITICAL FLUID SYSTEM
Secondary abstract:	The goal of the presented diploma thesis was to study the thermodynamic properties of a system polymer/supercritical fluid, compare our results with those of a similar system and to create a thermodynamic model for the gas applied for experiments. The thermodynamic properties of interest were the solubility S and the diffusivity D of gas molecules in the molten polymer. For this purpose, all the experiments done in the autoclave, were conducted at constant temperatures. The investigated temperatures were 70°C and 90°C, while the pressure ranged between 100 bar and 250 bar. The weighed sample placed in the autoclave was exposed to a certain temperature and pressure for about one day after which an equlibrium state was established. After a quick depressurization to atmospheric pressure, the weight loss of the sample was observed. A comparison between our results for D and those of a similar binary system, both at 70°C, was done. The thermodynamic model made in Wolfram Mathematica was based upon the Peng-Robinson (PR) equations of state. Our model assumes the gas density as a function of pressure and temperature. The main findings of the diploma thesis so: The solubility increases with pressure at both temperatures. The diffusivity at both temperatures increases until it reached it's maximum value, then started decreasing again as the pressure increased even further. The comparison of diffusivity with a similar system showed a comparible trend, but a substancial difference in values for D.
Secondary keywords:	polyethylene glicol;supercritical sulphur hexafluoride;autoclave;diffusivity;solubility;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	IX, 36 str.
ID:	8727828