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Influence of linear low density polyethylene on flow of recycled polyethylene
Křivánková, Eliška ; Poláček, Petr (referee) ; Bálková, Radka (advisor)
The work deals with the study of rheological behavior of recycled polyethylene (rPE) and the influence of linear low density polyethylene (LLD). The addition of LLD, which is added into rPE in order to set melt flow index and processing conditions, was 5–20 %. The received rPE was characterized by Thermogravimetry and Differential Scanning Calorimetry. Rheological measurements were performed on a reometer with plate-plate geometry in oscillatory mode (deformation of 0.25%, frequency range 0.01–100 Hz and temperature of 140, 170, 180 and 190 °C) and in flow mode (shear) at 190 °C and the shear rate 0,001–100 1/s. The recycled material contained low density polyethylene and LLD in a range approx. 1 : 1 and small amount of chalk and polypropylene. Complex viscosity and complex shear modulus together with their components were evaluated from oscillatory measurements of rPE, blends and neat polymer components. The change of microstructure, molecular weight and its distribution was evaluated as well. The melt stability in time was evaluated from flow measurements together with zero shear viscosity and melt elasticity. Miscibility of melt blends was evaluated from both type of measurements. It was found that the addition of 5–15% of LLD shifted rheological behavior of rPE into that of LLD but rheological behavior of the blend with the addition of 20% of LLD is the same as that of rPE. The reason is not different content of short and long branches but specific interaction of macromulecules. This knowledge may facilitate to set proper conditions of further processing of rPE regarding its composition.
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Study on flow and viscoelastic properties of laboratory prepared synovial fluids by macrorheological techniques
Veldamonová, Aneta ; Heger, Richard (referee) ; Smilek, Jiří (advisor)
This bachelor thesis deals with preparation and characterization of synthetic synovial fluid. Preparation was focused mostly on finding proper ratios of substances existing in real synovial fluid which have influence on viscoelastic properties. Based on study of literature, these substances are hyaluronic acid, lubricin, phospholipids and proteins. Samples of real synovial fluid from horse hock acquired from University of veterinary and pharmaceutical sciences Brno were tested for comparation with synthetically prepared synovial fluid. Both synthetic and real synovial fluid were characterized by macrorheological techniques. The experimentally obtained data were then compared with data from the patent on which the preparation of synthetic synovial fluid was based on. Thermogravimetry and isothermal thermogravimetry were used as additional method for the study of moisture and water binding of synovial fluids.
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The influence of alcohols on the flow properties of sodium hyaluronate
Habartová, Lucie ; Pekař, Miloslav (referee) ; Smilek, Jiří (advisor)
This bachelor’s thesis examines the influence of alcohol presence on the conformation of sodium hyaluronate aqueous solutions primarily about the use of flow methods utilizing. Two molecule masses of sodium hyaluronan were studied, namely 1500-1750 kDa further referred to as high-molecular sodium hyaluronan and 500-750 kDa referred to as low-molecular. The flow and viscosity properties of high-molecular sodium hyaluronate have been studied in the presence of methanol, ethanol, isopropyl alcohol and terc-butanol in the concentration range 0-80 wt. %. Low-molecular sodium hyaluronate, and above all its flow and viscosity properties, were measured in the presence of ethanol and isopropyl alcohol in the concentration range 0-80 wt. %. Based on measured data, viscosities were assessed at infinitesimal stresses consistent with zero-rate viscosity. The high-molecular sodium hyaluronate ranged up to 327 mPas in terc-butanol solution. Viscosity values increased with the increasing length of the alcohol chain. The low-molecular sodium hyaluronate reached a maximum of 39 mPas in an isopropyl alcohol solution. The viscosity curves of low-molecular sodium hyaluronate were close to that of the Newtonian liquid.
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Development of cosmetic cream fulfilling standards of CPK certification
Zinkovska, Natalia ; Hurčíková, Andrea (referee) ; Smilek, Jiří (advisor)
The aim of this diploma thesis is to propose a recipe of natural BB-creams with the desired properties (different color shades, that will be suitable for Central European skin type; flow properties, texture, spreadability, stability). The experimental part of the thesis is mainly focused on the development of BB-cream formulas. Several different formulations with diverse dispersion medium (water and aloe vera/water in a suitable ratio) have been proposed, and three different shades of BB-cream have been developed. The flow properties (viscosity) of the samples were measured, accelerated stability tests were realized by using the dispersion analyzer LUMISizer, the obtained results were correlated with the results of stress temperature tests. The results of the rheological analysis showed that the flow properties of the creams are comparable with commercially available preparations. Stress temperature tests have shown that prepared samples remain stable over 4 cycles (12 weeks) of changing storage temperature, accelerated destabilization tests performed by LUMISizer confirmed their stability. The colour coordinates of the developed shades were measured using a spectrophotometer and compared with commercial analogues. Also the questionnaire for sensory evaluation of preparations for more comprehensive analysis of prepared BB-creams was developed. The 25 female respondents of different ages participated in servey. The results of sensory evaluation showed that textural properties of developed creams are satisfactory for potential consumers.
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Formulation and characterization of hydrogels for local treatment of musculoskeletal infections
Drdová, Pavlína ; Šnejdrová, Eva (advisor) ; Vraníková, Barbora (referee)
Charles University Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical Technology Author: Pavlína Drdová Title of thesis: Formulation and characterization of hydrogels for local treatement of musculoskeletal infection Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Local anti-infective therapy for musculoskeletal infections eliminates systemic drug toxicity. By selecting a suitable drug delivery system, higher drug concentrations at the site of infection and sustained release can be achieved. Such a system may be gels, formulated and tested in the submitted diploma thesis. The theoretical part of the work was devoted to the description of musculoskeletal infections and their treatment, characterization of gels and their use in parenteral administration. Hydrophilic gels based on hypromellose, carrageenan, gelatin and fish gelatin containing vamcomycin hydrochloride and gentamicin sulfate were formulated. Flow and viscoelastic properties were tested on a rotational rheometer. The analysis of flow curves by the Power law model proved a non-Newtonian type of flow. The most sensitive to applied stress is a 3 % hypromellose gel, the least a dispersion of iota-carrageenan with povidone 25. Viscoelastic properties were evaluated based on elastic, viscous and complex modulus, phase angle and yield...
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Formulation and characterization of hydrogels for local treatment of musculoskeletal infections
Drdová, Pavlína ; Šnejdrová, Eva (advisor) ; Vraníková, Barbora (referee)
Charles University Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical Technology Author: Pavlína Drdová Title of thesis: Formulation and characterization of hydrogels for local treatement of musculoskeletal infection Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Local anti-infective therapy for musculoskeletal infections eliminates systemic drug toxicity. By selecting a suitable drug delivery system, higher drug concentrations at the site of infection and sustained release can be achieved. Such a system may be gels, formulated and tested in the submitted diploma thesis. The theoretical part of the work was devoted to the description of musculoskeletal infections and their treatment, characterization of gels and their use in parenteral administration. Hydrophilic gels based on hypromellose, carrageenan, gelatin and fish gelatin containing vamcomycin hydrochloride and gentamicin sulfate were formulated. Flow and viscoelastic properties were tested on a rotational rheometer. The analysis of flow curves by the Power law model proved a non-Newtonian type of flow. The most sensitive to applied stress is a 3 % hypromellose gel, the least a dispersion of iota-carrageenan with povidone 25. Viscoelastic properties were evaluated based on elastic, viscous and complex modulus, phase angle and yield...
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The influence of alcohols on the flow properties of sodium hyaluronate
Habartová, Lucie ; Pekař, Miloslav (referee) ; Smilek, Jiří (advisor)
This bachelor’s thesis examines the influence of alcohol presence on the conformation of sodium hyaluronate aqueous solutions primarily about the use of flow methods utilizing. Two molecule masses of sodium hyaluronan were studied, namely 1500-1750 kDa further referred to as high-molecular sodium hyaluronan and 500-750 kDa referred to as low-molecular. The flow and viscosity properties of high-molecular sodium hyaluronate have been studied in the presence of methanol, ethanol, isopropyl alcohol and terc-butanol in the concentration range 0-80 wt. %. Low-molecular sodium hyaluronate, and above all its flow and viscosity properties, were measured in the presence of ethanol and isopropyl alcohol in the concentration range 0-80 wt. %. Based on measured data, viscosities were assessed at infinitesimal stresses consistent with zero-rate viscosity. The high-molecular sodium hyaluronate ranged up to 327 mPas in terc-butanol solution. Viscosity values increased with the increasing length of the alcohol chain. The low-molecular sodium hyaluronate reached a maximum of 39 mPas in an isopropyl alcohol solution. The viscosity curves of low-molecular sodium hyaluronate were close to that of the Newtonian liquid.
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Development of cosmetic cream fulfilling standards of CPK certification
Zinkovska, Natalia ; Hurčíková, Andrea (referee) ; Smilek, Jiří (advisor)
The aim of this diploma thesis is to propose a recipe of natural BB-creams with the desired properties (different color shades, that will be suitable for Central European skin type; flow properties, texture, spreadability, stability). The experimental part of the thesis is mainly focused on the development of BB-cream formulas. Several different formulations with diverse dispersion medium (water and aloe vera/water in a suitable ratio) have been proposed, and three different shades of BB-cream have been developed. The flow properties (viscosity) of the samples were measured, accelerated stability tests were realized by using the dispersion analyzer LUMISizer, the obtained results were correlated with the results of stress temperature tests. The results of the rheological analysis showed that the flow properties of the creams are comparable with commercially available preparations. Stress temperature tests have shown that prepared samples remain stable over 4 cycles (12 weeks) of changing storage temperature, accelerated destabilization tests performed by LUMISizer confirmed their stability. The colour coordinates of the developed shades were measured using a spectrophotometer and compared with commercial analogues. Also the questionnaire for sensory evaluation of preparations for more comprehensive analysis of prepared BB-creams was developed. The 25 female respondents of different ages participated in servey. The results of sensory evaluation showed that textural properties of developed creams are satisfactory for potential consumers.
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Study on flow and viscoelastic properties of laboratory prepared synovial fluids by macrorheological techniques
Veldamonová, Aneta ; Heger, Richard (referee) ; Smilek, Jiří (advisor)
This bachelor thesis deals with preparation and characterization of synthetic synovial fluid. Preparation was focused mostly on finding proper ratios of substances existing in real synovial fluid which have influence on viscoelastic properties. Based on study of literature, these substances are hyaluronic acid, lubricin, phospholipids and proteins. Samples of real synovial fluid from horse hock acquired from University of veterinary and pharmaceutical sciences Brno were tested for comparation with synthetically prepared synovial fluid. Both synthetic and real synovial fluid were characterized by macrorheological techniques. The experimentally obtained data were then compared with data from the patent on which the preparation of synthetic synovial fluid was based on. Thermogravimetry and isothermal thermogravimetry were used as additional method for the study of moisture and water binding of synovial fluids.
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Influence of linear low density polyethylene on flow of recycled polyethylene
Křivánková, Eliška ; Poláček, Petr (referee) ; Bálková, Radka (advisor)
The work deals with the study of rheological behavior of recycled polyethylene (rPE) and the influence of linear low density polyethylene (LLD). The addition of LLD, which is added into rPE in order to set melt flow index and processing conditions, was 5–20 %. The received rPE was characterized by Thermogravimetry and Differential Scanning Calorimetry. Rheological measurements were performed on a reometer with plate-plate geometry in oscillatory mode (deformation of 0.25%, frequency range 0.01–100 Hz and temperature of 140, 170, 180 and 190 °C) and in flow mode (shear) at 190 °C and the shear rate 0,001–100 1/s. The recycled material contained low density polyethylene and LLD in a range approx. 1 : 1 and small amount of chalk and polypropylene. Complex viscosity and complex shear modulus together with their components were evaluated from oscillatory measurements of rPE, blends and neat polymer components. The change of microstructure, molecular weight and its distribution was evaluated as well. The melt stability in time was evaluated from flow measurements together with zero shear viscosity and melt elasticity. Miscibility of melt blends was evaluated from both type of measurements. It was found that the addition of 5–15% of LLD shifted rheological behavior of rPE into that of LLD but rheological behavior of the blend with the addition of 20% of LLD is the same as that of rPE. The reason is not different content of short and long branches but specific interaction of macromulecules. This knowledge may facilitate to set proper conditions of further processing of rPE regarding its composition.
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