Chitosan membrane has found applications in biomedical, wastewater treatment, and petrochemical fields that involve the use of silver ions (Ag+). However, mobility of Ag+ in chitosan membranes has seldom been studied. In this study, transport properties of Ag+ in chitosan membranes are studied in-depth, to determine diffusivity coefficient, permeability coefficient, and sorption uptake of Ag+ in chitosan. All parameters are evaluated based on the influence of feed concentration, membrane thickness and operating temperature. The diffusivity is determined from the time lag obtained from transient diffusion experiments. The permeability is determined from the steady state of permeation experimentally. The diffusivity and corresponding permeability coefficients of Ag+ in chitosan range from to 2.0 10-7 (cm2/s) and from 6.6 10-8 to 2.0 10-7 {mol m/[m2 s (mol/L)]}, respectively, over the conditions tested. Temperature dependencies of these two parameters are found to follow the Arrhenius relationship. Sorption uptake of the silver salt in chitosan correlates well with the Langmuir isotherm. Also determined from the sorption tests are degree of membrane swelling at different concentrations. This information allows diffusivity coefficients to be determined from the steady state permeation rate. These values of diffusivity are compared with that obtained using the time lag method.

In this work, a gradient of interpenetrating polymer networks, consisting of anionic and cationic polymers, has been investigated with respect to protein resistant properties and swelling characteristics at different pH and ionic strength conditions. The swelling and protein adsorption have been studied using \emph{in situ} spectroscopic ellipsometry(SE) and imaging surface plasmon resonance(iSPR) respectively. It has been shown that, by altering the buffer pH, the region of lowest protein adsorption on the surface could be moved laterally. The swelling has similarly been shown to respond to both changes in pH and ionic strength. Additionally, the arise of surface charge and the polymer swelling in solution, both a consequence of the ionisation of fixed charges on the polymer, have been indicated to occur at different buffer pH. The studied polymer systems show promising properties for future applications in, for example, the biosensor area, where the surface chemistry can be tailor-made to work optimally in a given environment.

Expansive soils are a worldwide problem that poses several challenges for civil engineers. Such soils swell when given an access to water and shrink when they dry out. The most common and economical method for stabilizing these soils is using admixtures that prevent volume changes. In this study the effect of using Bigadic zeolite (boron by-product) in reducing the swelling potential is examined. The expansive soil is prepared in the laboratory by mixturing kaolinite and bentonite. Bigadic zeolite (boron by-product) is added to the soil at 0 to 25 percent by weight. Grain size distribution, Atterberg limits and swell percent and rate of swell of the mixtures are determined. Specimens are cured for 7 and 28 days. As a result of the experimental study, it was seen that addition of Bigadic zeolite (boronby-product) decreased swelling potential and rate of swell of the artificially prepared expansive soil specimen at laboratory conditions. The swell percentage and rate of swell of the stabilized specimens are affected positively by curing.

Acrylonitrile based engineering random copolymers were prepared via one step emulsion polymerization using ammonium persulfate (initiator), 1-dodecanthiol (chain transfer agent) and DOWFAX 8390 (surfactant) in the presence of water at approximately 65 0C. Three copolymer compositions were studied for novel polyacrylonitrile, (PAN)-polyhydroxyethyl acrylate (PHEA), PAN-polybutyl acrylate (PBA), novel PAN-polyt-butyl acrylate (PtBA), PAN-polyethyl acrylate (PEA) and PAN-polymethyl acrylate (PMA) with acrylate content varying from 8, 12 and 16 molar percent. Infrared spectroscopy, proton and carbon NMR were successfully utilized to confirm the chemical structure of copolymers. In order to determine the comonomer compositions in the copolymer structure, proton nuclear magnetic resonance, 1H NMR studies were carried out. Thermal (TGA, DSC) and mechanical properties of homo and copolymers were also investigated. Intrinsic viscosity (IV) measurements in dimethyl formamide (DMF) solution revealed that the molecular weight of the copolymers were quite enough to form ductile films. In this study, hydrogels and their copolymers of acrylonitrile (PAN-PHEA) were also studied. Some properties of the free standing copolymer films such as / swelling behaviors and densities were evaluated. It was also demonstrated that the nanocomposites of these copolymers could be utilized in filtration technology. Hence, novel PAN(88)-co-PMA(12) and polyaniline (PANI) nanocomposites were prepared at various PANI loadings to remove toxic chromium(VI) solution from water. Chemical structure, swelling and fracture morphology of the nanocomposites membranes were studied. It was observed that PANI had a great impact on the chromium removal. Permeate flux and rejection of chromium(VI) were demonstrated for various pHs and chromium(VI) concentrations. Finally, influences of comonomer composition on the thermal properties of the copolymers were investigated to input their structure property relation.

Acrylamide based hydrogels were synthesized through copolymerization reaction of allyl methacrylate with acrylamide. Copolymerization reactions were carried out with solution polymerization in tetrahydrofuran by using &alpha / -&alpha / -azoisobutyronitrile as an initiator at 60 0 C. Three copolymer compositions were studied having 5, 15, 25 molar percentage of allyl methacrylate as feed concentrations. The synthesized copolymers were characterized by FTIR, NMR, DSC, TGA and GPC. 1H-NMR spectra were used to confirm the chemical structures of the copolymers and to determine the comonomer compositions of the copolymers. DSC and TGA analysis were conducted to determine the thermal properties of the copolymers and TGA results showed that copolymers have two step degradation behavior. Molecular weights of the copolymers were determined by GPC. Swelling capacities of the obtained hydrogels were investigated and swelling capacity of the gels reached to 77% as maximum value.

In this study, it was aimed to develop conservation methodologies for the historic sandstones using the case of Nemrut Mount Monument to help their survival in open air conditions. The main conservation approach of this study was holistic as well as aiming at minimum intervention targeted to the problem areas. The most important weathering forms of Nemrut Sandstones were material loss due to loss of scales and granular disintegration as well as detachments by scales, back weathering due to loss of scales, cracking, granular disintegration, rounding/notching and discoloration/biological deposition. Deterioration mechanisms of sandstones were studied on deteriorated and relatively sound sandstones by nondestructive methods of UPV and QIRT, and by microstructural analyses using thin section, XRD and SEM-EDX analyses. In addition, the changes in physical and physcomechanical properties such as, color, bulk density, effective porosity, hydric, hygric and thermal dilatation and CEC of clays were determined. Sandstone deterioration was caused by swelling of clay minerals distributed in their matrix and clay accumulations between the detaching scales. Considerable thermal dilatation characteristics was also an important decay factor. Iron oxides caused discoloration at the surfaces, their phase changes was thought to be important in decay. The use of surfactant DAA, to control clay swelling was found to decrease the hydric dilatation by 40%. The consolidation treatments with nanosilica and silicate dispersions namely Funcosil KSE500STE, SytonX3, KSE300 and KSE100 have improved physicomechanical properties as followed by UPV measurements and decreased hydric dilatation. Their long term behaviour needed to be further investigated.

<p>Processing of nanostructured WC-Co and W-Co powders,modelling of Fe-Mn-Si alloy, swelling of Fe-Cu alloy, andmechanical properties and sintering of Fe-Mn-Si steels havebeen studied in the present thesis.</p><p>W-Co precursors made by chemical synthesis were used toproduce nanostructured WCCo and W-Co powders by calcination,reduction and carburization. The phase constituents in thecalcined powders depend on temperature and atmospheres. Cobaltcan accelerate the reduction rate of the W-Co precursors as acatalyst, and cobalt influences the formation of intermediatephases during the reduction of the precursors.</p><p>The ratio of carbon monoxide to carbon dioxide controlscarburization process, gives different intermediate phases andcarburization rates. There exist several intermediate phases: W₆Co₆C, W₃Co₃C, W₂C due to varying carbon monoxide content in thecarburization gases. Nanostructured WC-Co powders with aparticle size of 20-50 nm have been obtained.</p><p>The effect of silicon content on the particle sizedistribution of milled Fe-Mn-Si master alloy powders is muchmore significant than that of manganese content. A finer finalparticle size can be obtained in the alloy powders with highersilicon compositions. Long time milling results in theagglomeration of small particles. The grinding process can bedescribed using classic batch grinding equation based on thepopulation balance model. A swelling model for Fe-Cu alloyssintered at the temperatures above the melting point of copperhas been established based on the penetration mechanism. In themodel, the particle coordination number and heating rate wereused to express the porosity and the thickness of the diffusionlayers between iron and copper particles respectively.</p><p>The effects of sintering temperature and time on theproperties of sintered steels have been studied. Fe-Mn-Simaster alloys made by cast-milling, atomizing, and acombination of atomization and milling have been covered. Themilled, and atomizationmilled alloy steels showed goodmechanical properties with small dimensional change. Transientliquid phase of the Fe-Mn-Si alloys accelerates densification,and offer fast diffusion of alloying elements. The addition ofa small amount of Fe-Mn-Si master alloy to Astaloy 85Mo powdercan lead to high strength with zero dimensional change.</p><p><b>Key words:</b>Processing; Modelling; Nanostructured powder;WC-Co; W-Co; Calcination; Reduction; Carburization; Particlesize; Sintered steel; Fe-Cu alloy; Swelling; Fe-Mn-Si masteralloy; Mechanical properties; Sintering parameters.</p>

For the development of smart surfaces high attention is focused on stimuli-responsive polymers. Since type and rate of response to environmental stimuli can be regulated by chain length, composition, architecture and topology, polymer films offer a variety of opportunities to develop such stimuli-responsive surfaces. Here polymer brush surfaces designed for a controlled adsorption of proteins and a switchable activity of immobilized enzymes are presented. The work is focused on temperature as well as pH-sensitive binary brushes, consisting of poly(N-isopropylacrylamide) (PNIPAAm) and poly(acrylic acid) (PAA), and their swelling behavior as well as their protein adsorption affinity is compared to the corresponding homopolymer brushes. All polymer brushes are covalently grafted by ester bonds to an anchoring layer of poly(glycidyl methacrylate), that itself is grafted via ether bonds to a silicon surface. Methodical investigations of layer thickness and refractive index of the brushes in the swollen state and after protein adsorption are carried out with in-situ spectroscopic ellipsometry, varying the brush composition and the solution parameters pH, salt concentration and temperature. The ellipsometric findings are correlated to results of contact angle, atomic force microscopy and zeta-potential measurements as well as colorimetric assays of enzyme activities at the brush surface. Furthermore the swelling of PNIPAAm brushes and protein adsorption at PAA Guiselin brushes are investigated in more detail with attenuated total reflexion Fourier-transform infrared spectroscopy and quartz crystal microbalance with dissipation, respectively.

Für die visuelle Wahrnehmung im Gehirn spielt die ungestörte Funktion von Neuronen und Gliazellen in der Netzhaut eine entscheidende Rolle. Viele schädigende Prozesse wie Entzündungen, Ischämien oder Traumata können zur Ödementstehung in der Netzhaut führen. Da die Netzhaut entwicklungsgeschichtlich einen vorverlagerten Teil des Zwischenhirns darstellt, lassen sich die pathophysiologischen Zusammenhänge, die zur Entstehung eines Netzhautödems führen, auch auf die Ödementstehung im Gehirn übertragen. Diese Arbeit beschäftigt sich mit dem Phänomen der Zellvolumenregulation von Müllerzellen – den hauptsächlich in der Netzhaut anzutreffenden Gliazellen – und leistet damit einen Beitrag zur Grundlagenerforschung der Ödementstehung in neuronalen Geweben. Die im Rahmen von Ödementstehungen regelmäßig zu beobachtenden Gefäßpermeabilitätserhöhungen führen in neuronalen Geweben auch zur Extravasation von Albumin. Unter diesem Gesichtspunkt untersucht die vorliegende Arbeit den Einfluss von bovinem Serumalbumin auf die Müllerzellen und die damit verbundenen Mechanismen am Modell der Netzhaut von Ratten.

The aim of this thesis “Interactions of biodegradable drug carriers with hydrophilic medium” is the study of polymer-hydrophilic medium interactions from the point of view of swelling, erosion and glass transition. In the theoretical part attention was paid to basic information about polyester amides and polyesters with molecule linear, branched, and chain extended. In this part, some basic relations were used, concerning various aspects of biodegradation of polymers, thermal analysis of amorphous phase of polymers and pharmaceutical particulate systems. The main part of the thesis is focused on experiment. Fifteen recently synthesized oligomeric and polymeric carriers were studied in the aspect of their swelling and erosion course. Some of these oligoesters with molecular linear constitution were evaluated during in vitro degradation process via glass transition tested by DSC method measurements. No correlation signs between swelling kinetics and glass transition temperature values course were found. These two molecular relaxation parameters are the manifestations of different mechanism. Swelling extent is influenced by osmotic phenomena, whilst glass transitions by molecule polarization effects. This work is one of the first steps examining these drug carriers. The results of this work will be used in choosing perspective drug carriers and in further researches. / Šio darbo „Biodegraduojančių vaistų nešėjų sąveika su hidrofiline terpe“ tikslas ištirti polimero bei hidrofilinės terpės sąveiką atsižvelgiant į brinkimą, eroziją bei stiklėjimo temperatūros pokyčius, galimą ryšį tarp polimero brinkimo ir stiklėjimo temperatūros, apžvelgti nano ir mikro dalelių paruošimo bei įvertinimo teoriją. Literatūros apžvalgoje dėmesys skiriamas informacijai apie poliesteramidus ir linijinius, šakotus ar praplėstos grandinės poliesterius. Šioje dalyje aptariami įvairūs polimerų biodegradacijos, amorfinės fazės polimerų terminės analizės aspektai, taip pat nano bei mikrodalelės kaip vaisto forma. Pagrindiniai darbo uždaviniai yra ištirti penkiolika neseniai susintetintų oligomerinių bei polimerinių vaistų nešėjų atsižvelgiant į jų brinkimą bei eroziją, įvertinti kai kurių linijinių oligoesterių degradacija in vitro atsižvelgiant į stiklėjimo temperatūrą matuojant diferencinės skenuojančios kalorimetrijos metodu. Atkreiptas dėmesys į galimą ryšį tarp stiklėjimo temperatūros ir brinkimo kinetikos, kurio nepastebėta; manoma, kad dėl to, jog molekulės grandinės atsipalaidavimas pasireiškia dėl skirtingų mechanizmų. Brinkimo laipsnis priklauso nuo osmotinių reiškinių, o stiklėjimo temperatūrai įtaką daro molekulės poliarizacija. Šis darbas yra pradinis etapas tiriant šiuos polimerus. Šio darbo rezultatai padės atrenkant perspektyvias medžiagas tolimesniems tyrimams, prognozuojant galimas jų panaudojimo galimybes.