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Acidobasic behavior of carboxymethylcellulose solutions
Teslíková, Ivana ; Kislinger, Jiří (referee) ; Janeček, Jiří (advisor)
This work concerns with the study of acidobasic behavior of solutions of sodium salts of carboxymethylcellulose (CMC-Na). This behavior was investigated using acidimetric titrations of the salt solutions with potentiometric and conductometric indications. In order to determine the content of carboxylic groups in two different samples of CMC-Na (M1=90 kDa, DS1=0.7; M2=700 kDa, DS2=0.9), we employed the method of Ray von Wandruzska, originally proposed for the determination of the acidity of humic substances. The values of the degree of substitution (DS) obtained using this method correspond to the values declared by the producer. The small differences (of the order few percentage points) can be attributed to the humidity of the samples. The acidimetric titrations were performed also for solutions with different ionic strengths. There is an apparent effect of the ionic strength on the shape of titration curves; nevertheless these data were not used for any theoretical interpretation.
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Recovery of celulose from wastewater
Kobzová, Kamila ; Úterský, Michal (referee) ; Hlavínek, Petr (advisor)
The goal of this bachelor’s thesis is to point to amount of cellulose in water-waste, which manly came from people homes. Other goal is to show possibilities how to obtain this cellulose from sewage in other countries and how to use it afterward. Practical part of this thesis focuses on project which filter cellulose in sewage treatment plant in Brno-Modřice.
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Ageing of cotton fabric as determined from polymerization degree change
Flimelová, Miroslava ; Nasadil, Petr (referee) ; Kučerík, Jiří (advisor)
The degree of polymerization (DP) is the main factor which plays a role in cellulose aging. The adverse consequence of cellulose fibers aging is the deterioration of mechanical and optical properties. Viscometry is a technique which is frequently used for determination of degree of polymerization of cellulose fibers. The aim of the work was to determine the degree of polymerization of cotton fabrics and to investigate the dependence of DP on number of washing and dying. Next task was to investigate if there exists a corellation between DP and results from thermal and thermo-oxidative degradation studied by methods of thermal analysis. First, the traditional viscometry was employed to determine DP of cellulose fibers. It has been demonstrated that number of washing and dying decreases the DP. In the second part the differential scanning calorimetry (DSC) and thermogravimetry (TG) were used. DSC provided values of combustion heat and TG allowed the detail evaluation of degradation steps; obtained results were further used for correlation with DP. Methods of thermal analysis revealed differences between cotton wool and treated fabrics. Combustion heat did not show any correlation with DP. In contrast, results from TG suggested some promising correlations which could be used for the prediction of cotton fabrics DP using thermal analysis in the future.
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Immobilization of selected glycanohydrolases
Reichstädter, Marek ; Trachtová, Štěpánka (referee) ; Omelková, Jiřina (advisor)
The theoretical part of this thesis deals with cellulolytic enzymes, their microbial producers, the possibilities of using such enzymes in the industry and how can be enzymes - not only cellulolytic - immobilized. Experimental part examines the preparations created by immobilizing various amounts of the commercially used cellulolytic complex Cellulast 1.5L onto various synthetic carriers made of polyethylene terephthalate - commercially used Sorsilen, PET carrier and glutaraldehyde-treated PET carrier. Enzyme activity of these preparations was determined by Somogyi - Nelson method by spectrophotometry. For the highest activity immobilized preparation was determined the temperature- and the pH-optimum. The difference in effects change between the free and immobilized enzyme by measuring viscosity decrease of the substrate depending on the degradation of glycosidic bonds was also studied.
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Family House
Mázl, Michal ; Němeček, Martin (referee) ; Kalousek, Miloš (advisor)
The aim of my bachelor thesis is a project of passive family house with design office. New family house is located in the northern part of Pístovice near Vyškov. It is a single-storey house with conservatory and partial basement. The supporting structural system is combined. Wooden structure is insulated with blown cellulose and flat roof with polystyrene. The building is based on concrete slab insulated from the bottom with the foam glass granulate. There is a winter garden, which is located on the south facade. Built-up area is 240.5 m
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Studying the properties of fiber cement composites
Cederová, Kristýna ; Hoško, Marek (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis deals with fiber-cement composites. Input materials are investigated for the production of fiber cement, are examined, the production and parameters of the pulp were monitored. Further, Hatschek's production technology and requirements for corrugated fiber-cement roofing are described. In the practical part the individual input materials and parameters of ground pulp were verified. The problem with production of samples and difference in the fineness of pulp milling in fiber cement products has been solved.
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Výzkum alternativních izolačních materiálů a jejich použití v dřevostavbách
Brázdová, Šárka
This bachelor thesis, based in a research, is concerned with the comparison of alternative insulation materials, namely cellulose insulation and fungal mycelium insulation and their use in wooden buildings.. Both types of materials are used in a timber frame building. The theoretical part focuses on the characteristics and possible applications of the insulation materials. The second part of the thesis presents the measured values, their assessment and comparison.
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Use of organic fibers in fine-grained cement composites and their influence on the monitored properties
Mazán, Tomáš ; Ondráček, Michal (referee) ; Křížová, Klára (advisor)
The diploma thesis describes the possibilities of using organic fibres to improve the properties of cement composites at high temperatures. The theoretical part of the thesis deals with the behaviour of the different components of concrete and concretes in fire. A substantial part is devoted to the types of fibres, the method of dosage and the effect of their use on selected parameters. The practical part of the thesis is based on the developed methodology. On the basis of the results obtained, a summary of the behaviour and transformations of different types of organic fibres when exposed to temperatures from 20 to 800 °C was compiled. Furthermore, the observed parameters and the effect of the fibres, especially on the strength of the composite loaded at high temperature, are evaluated. The final of thesis concludes with recommendations for fibre dosage and the suitability of using recycled fibres.
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Utilization of waste banana peels for packaging materials
Vachta, Jonáš ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with isolation of cellulose from waste banana peels and it’s use as a filler in composite films. The aim of this work was to prepare a bioplastic capable of being an eco-friendly alternative to conventional polymers with a potential for application in the packaging industry. The cellulose was isolated from banana peels using a method combination of alkalic and acidic hydrolysis and bleaching by sodium chlorite. The samples after isolation were characterised by Fourier transform infrared spectroscopy (FT-IR) and their average particle size was determined by microscope observation. Subsequently, composite films were prepared using agar and starch matrix, glycerol as plasticizer and isolated cellulose as filler in various concentrations to assess the effect of added cellulose on the properties of the resulting bioplastics. Characterization of the prepared bioplastics included FT-IR measurement, surface examination by a scanning electron microscope (SEM) and the determination of mechanical properties by measuring tensile strength, elongation at break and Young’s modulus. It was found that the addition of cellulose from banana peels has a positive effect on the mechanical properties of all prepared agar- or strach-based composites, with the exception of elongation at break in agar films, where there was a slight decrease compared to the reference films.
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