Formulacija in karakterizacija naravnih polimernih nosilcev za vezavo pigmentov : doktorska disertacija

slovenian

doktorska dela

2014

Univerza v Mariboru, Fakulteta za kemijo in kemijsko tehnologijo

The first part of the dissertation is devoted to research of phase equilibria of triglycerides in sub and supercritical fluids. Data is key for further planning and formulation of high-pressure separation processes because they contributed to the improvement of certain industrial processes towards environmental protection and product quality. To determine the solubility of the glycerol tristearate-condensed gases and glycerol trioleate-condensed gases were used a high-pressure optical cell. The measurements were performed at different temperatures (30, 50, 70 and 90 ° C) and pressures up to 600 bar. The aim of our experimental work was to obtain information on the phase equilibria of glycerol and glycerol trioleate tristearate systems in supercritical CO2 and SF6, which are crucial for optimizing high-pressure separation and formulation processes. Data on the phase equilibria of glycerol tristearate-SF6 and SF6-glycerol trioleate in the literature is not. The data obtained are new and open up new prospects for the use of SF6 as a solvent for various media. For investigation of the influence of pressure to a temperature of the melting point and the determination of the melting heat of the various gas (nitrogen and CO2), we used high-pressure DSC. We have also determined the solubility and diffusion coefficient of the supercritical CO2 in a variety of natural polymers, which are used in the food industry as a binder, and in the various celluloses and starches. CO2 solubility in the polymer is dependent on temperature and pressure, as well as causing its swelling and thereby lowering the viscosity of the polymer. By increasing the solubility of CO2 in the polymer also increases the weight of the polymer. To determine the solubility of CO2 and diffusion, we used a magnetic suspension balance. The measurements were performed by means of magnetic suspension scales at different temperatures (40, 60, and 80 ° C) and pressures up to 300 bar. We determined high levels of solubility and diffusion coefficients of polymers when exposed to SC CO2. In any case, there was no dissolution of the polymer, but the polymer can absorb CO2 and swollen. From the obtained data it is clear that the solubility of CO2 in the polymers by increasing the pressure increases and decreases with increasing in temperature. Increasing pressure causes an increase in gas density and to improve the solubility, thereby increasing the volume of the polymer. By increasing the temperature is decreasing gas density. Diffusion coefficients of CO2 are dependent on the concentration of CO2 in the polymer. At the beginning, the value of the diffusion coefficient by increasing the solubility of the rise until the CO2 does not fill all free of voids in the polymer, and then apply these values to fall due to the action of hydrostatic pressure. By determining the solubility and diffusion coefficient of CO2 in polymers at a given temperature and pressure, we gain more information about the phase equilibrium polymer-gas, which are important for understanding and optimizing the process parameters. In the last part of the doctoral dissertation are bound natural yellow colorant curcumin from spices and 10% of the liquid extract on carriers such as triglycerides, polyethylene glycol, cyclodextrin, cellulose, and starches. We studied different combinations of colors and a mixture of various media with supercritical CO2. Micronized powder product dyes curcuma we measured the average size and the average size distribution of the resulting particles. We also supercritical and conventional extraction of turmeric (Curcuma longa L.). We have several different conventional extractions: extraction with cold solvent in a flask, Soxhlet extraction, ultrasonic extraction and extraction with conventional solvent at elevated pressures. The resulting extracts were analyzed antioxidant activity by means of using the free-radical methods. We are also in extracts determine the antioxidant value of the standard TROLOX.

07.08.2023