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Properties of chitin whisker reinforced poly(acrylic acid) compositesOfem, Michael January 2015 (has links)
Composites, in which the matrix and the reinforcing fillers are respectively, poly(acrylic acid) (PAA) with two different molecular weights, and chitin whiskers (CHW) were successfully prepared using an evaporation method. The weight fraction of CHW was varied from 0.03 to 0.73. Mechanical and thermal properties and crystallinity of the composites were characterised using tensile testing, differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction. The tensile strength of the composite increased up to 11 wt % CHW after which it decreased. XRD characterisation showed a decrease in crystalline index, crystalline size, chitin crystalline peak and intensity as the content of PAA and its molecular weight increased. Raman spectroscopy was used for the first time to monitor the deformation of chitin film and CHW reinforced PAA composites. The Raman band located at 1622 cm^(-1) was monitored for deformation. On application of tensile deformation the Raman band initially located at 1622 cm^(-1) shifted toward a lower wavenumber. Raman band shift rates of -1.85 cm^(-1)/% for chitin film and -0.59 and -0.25 cm^(-1)/% for 73 and 23 wt % CHW content, respectively, were measured. The modulus of a single chitin whisker and composites were found to be 115, 37 and 16 GPa respectively, for a two dimensional (2D) in-plane distribution of CHW. CHW within a PAA matrix did not show any preferential alignment in a polarised Raman. The Raman intensity ratio〖 I〗_1698 /I_1622 showed that the strongest interaction of the carboxylic group in the composites occured at 3 wt % CHW content. The interaction gradually reduced as the CHW content increased. 〖 CaCO〗_3 crystals were grown in CHW, PAA and CHW/PAA composites by a solution and evaporation casting method. In the absence of PAA and CHW, rhombohedral calcites were observed while rod-like aragonite polymorphs were seen when only PAA was used as a template. In the presence of only CHW, a morphological mixture of ellipsoidal and disc shape with traces of rhombohedral aggregate calcite were the features. In the presence of both PAA and CHW, the rhombohedral shape showed roughness with irregular faces while the vaterite polymorph continued to agglomerate with the observation of porosity at higher CHW content. The vaterite particles gradually decreased as the CHW content was decreased. At lower CHW content aragonite polymorph growth was favoured to the detriment of calcite. The results showed that the vaterite polymorph can be grown even at higher filler loading. The effect of 〖 CaCO〗_3 growth on the mechanical properties of CHW reinforced PAA indicated that better mechanical properties can be achieved at a CHW content of 3 wt % when compared with neat PAA and when 〖 CaCO〗_3 was not incorporated into the CHW/25PAA composites.
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Noncovalent Functionalization of Latex Particles using High Molecular Weight Surfactant for High-Performance CoatingsZheng, Lei 20 August 2019 (has links)
The expected outcome of this project is to develop a general strategy to functionalize dispersions, by noncovalent adsorption of HMW surfactants, ultimately for applications such as hydrophobic coatings with high hiding power and hardness, improved mechanical properties via pigment-latex interactions, improved substrate adhesion or improved freeze-thaw stability. So far, we have produced poly (methyl methacrylate-co-butyl acrylate) latexes in the presence of HMW surfactants via emulsion polymerization and demonstrated stronger adsorption of HMW surfactants on particle surface than sodium dodecyl sulfate (SDS). In addition, we have developed surfactant-free latexes, poly (methyl methacrylate-co-butyl acrylate-co-methacrylic acid), as models for post functionalization with high molecular weight surfactants. The successful transfer of surfactants onto particle surface from liquid crystals was indicated by the increase in zeta potential and confirmed via chemical shifts variation in 1H NMR spectra. Additionally, the HMW surfactants were used for dispersing hydrophobic inorganic particles, such as hydrophobic carbon black, in aqueous phase, providing an indication of the general applicability and versatility of our approach.
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Development of sustainable Re-Tanning Agents from Fungal Degradation of LignosulfonatesAmmenn, Jochen 03 June 2019 (has links)
Lignosulfonates are abundantly available by-products of the paper industry. In the vast majority of applications on leather lignosulfonates are physically blended with other chemistries to augment filling properties of the resulting products. We targeted to decrease the molecular weight of lignosulfonates using fungi to achieve increased application possibilities and to improve tanning properties. We screened various basidiomycotes for their capability to modify the molecular weight of calcium lignosulfonates and identified five species that actually polymerized the chosen lignosulfonate further. Only Irpex consors was found to depolymerize calcium lignosulfonate in surface and later in liquid cultures in our hands. We achieved a six fold reduction of the molecular weight determined by size exclusion chromatography.
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Studium afinity lepidel do buněčné stěny dřeva na submikrostrukturní úrovni / Study of the adheisve affinity into the wood cell wall at the sub-microstructural levelMitrenga, Ondřej January 2019 (has links)
This thesis focuses on the problematic of adhesive affinity into wood cell wall at the sub-microstructural level. The main subject of this thesis is research work of scholarly articles focused on the penetration of resins and polymers into the cell wall of the wood. In contains a description of the principles on which the used methods are based, and a summary of the results achieved. In the experiment, several method were used to investigate the possible penetration of selected methods adhesives into the structure of the cell wall. These are fluorescence microscopy, confocal microscopy, scannin electron microscopy (SEM) and transmission electron microscopy (TEM).
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Adhezní spolupůsobení lepidla s konstrukčním dřevem / interaction of adhesive with structural woodJanová, Petra January 2020 (has links)
This labor is based on penetration of adhesives into a wood cell walls. It focuses mainly on adhesives that are currently used for construction purposes. It also contains a methodics of selecting adhesives and wood, which will be used for glued joints and summarizes the methods used for detect these adhesives in the wood cell wall. It experimentally verifies the appropriate selection of the dye-solvent combination used in the adhesive.
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Deformačně napěťová analýza kyčelního spojení s totální endoprotézou s uvažováním otěru / Strain stress analysis of hip joint with thinking of wear after total hip endoprothesisEbringerová, Veronika January 2012 (has links)
The presented work deals with the creation of computational model of total hip endoprosthesis and the subsequent stress-strain analysis. The models of geometry of the pelvis and femur were created on base of CT data. In this model were fitted components od endoprosthesis, i.e. femoral stem and acetabular cup (metal and polyethylene pad) and also cement. On this system was subsequently modelled the rals loads conditions. Just the real loading of the prosthesis leads to the wear. It has a great influence on the quality of bone tissue, what is deteriorated. The deteriorated tissue was simulated under the acetabular component. The behaviour of the whole system is assessed on base of stress-strain analysis. This problems is very topical these days.
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Exploration of the Low-Molecular Weight Proteome of Tissue and Serum, with Applications to Disease Biomarker DiscoveryAlvarez, Meihwa Tanielle 24 June 2013 (has links)
The low-molecular weight proteome is of great interest due to the vast number of smaller proteins and peptides present within it, some of which are likely to be disease-related and may provide insights into disease mechanisms or even prediction and diagnosis. Serum is often the most preferred specimen for disease prediction or diagnosis, as it can be obtained less-invasively and its collection is fairly routine in a clinical setting. Although serum samples are one of the most preferred specimens for disease studies, additional disease information may also be obtained using other specimens, such as tissue. The study of tissue specimens can be extremely valuable in disease studies as it likely contains the highest concentration of potential markers for tissue related diseases. Therefore, despite the difficulty of sample collection, as compared to serum specimens, tissue specimens can be invaluable in studying tissue-related diseases. Tissue proteomics approaches for studying the low-molecular weight proteome of tissue have been infrequently described in the literature, which suggests the need to develop new methods or improve upon current proteomics approaches to better study this subset of the proteome in tissue. In this dissertation, I first report on a low-molecular weight tissue proteomics approach that we have developed based on a previously reported serum approach. As reported here, we conclude that this tissue proteomics approach cannot only distinguish the low-molecular weight proteome of different tissue types, but it also appears to be within the reproducibility range of other currently used proteomic approaches. Additionally, we also report on the use of a serum proteomics approach for biomarker discovery and identification in preeclampsia and endometriosis. These studies reveal many candidate biomarkers for preeclampsia prediction and endometriosis diagnosis. In the preeclampsia study we discovered several candidate biomarkers early in pregnancies (12-14 weeks gestation) that were able to predict preeclampsia later in pregnancy with statistical significance. In the endometriosis study, several candidate biomarkers were discovered that were statistically significant in diagnosing endometriosis. Further, for both preeclampsia and endometriosis, combinations of 3 or 4 biomarkers yielded an improved sensitivity and specificity in disease prediction and diagnosis with combined area under the curves of greater than 0.8. Thus, the low-molecular weight proteome of both tissue and serum could potentially provide important information regarding disease physiology, prediction, and diagnosis that may supplement our current understanding of these processes.
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DESIGN AND CHARACTERIZATION OF GELATIN HYDROGELS INCORPORATING LOW-MOLECULAR-WEIGHT DRUGS FOR TISSUE REGENERATION / 組織再生のための低分子薬物含有ゼラチンハイドロゲルの創製と評価Saito, Takashi 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19010号 / 工博第4052号 / 新制||工||1623(附属図書館) / 31961 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 田畑 泰彦, 教授 岩田 博夫, 教授 木村 俊作 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Fabrication of Well-Defined Architectures of Ultrahigh-Molecular-Weight Polymers by Living Radical Polymerization / リビングラジカル重合により合成した超高分子量ポリマーの高次構造形成Hsu, Shu-Yao 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19748号 / 工博第4203号 / 新制||工||1648(附属図書館) / 32784 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 辻井 敬亘, 教授 山子 茂, 教授 渡辺 宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Thermal Stabilization of Nanocellulose by Chemical Modification / 化学修飾によるナノセルロースの耐熱性向上Melissa, Agustin 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20449号 / 農博第2234号 / 新制||農||1050(附属図書館) / 学位論文||H29||N5070(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 矢野 浩之, 教授 木村 恒久, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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