In this work, hyperbranched aromatic polyesters-polyphenols based on 4,4-bis(4’ hydroxy¬phenyl)pentanoic acid (BHPPA) were prepared and, according to the authors knowledge, for the first time tested as precursors for polyurethane bulk resins and coatings. Comparison of poly-BHPPA with competing products The materials prepared in this work show better properties than their aliphatic polyester-polyol analoga based on 2,2-bis-(hydroxymethyl)propanoic acid (BHMPA). Especially, the solubility of poly-BHPPA in organic solvents is better and poly-BHPPAs also do not tend to microphase separation during their reaction with isocyanates, in contrast to poly-BHMPAs. The poly-BHPPA and the polyurethane networks made from them display higher Tg values than analogous poly- BHMPA compounds. Because of the high Tg of the reacting and final systems, curing must occur at elevated temperatures (90°C) in order to avoid undercure. The lower reactivity of phenolic OH groups prevents the reaction from being too fast at that temperature. A drawback of the polyurethanes based on the aromatic polyesters-polyols prepared is the lower thermal stability of their urethane bonds, if compared to aliphatic urethanes. An interesting possibility for future investigations would be the modification of the BHPPA monomer in order to change the OH functionality from phenolic to aliphatic OH, e.g. by replacement of the phenolic OH by hydroxymethyl or hydroxyethyl groups (requires a strong modification of the monomer synthesis) or simpler by reacting the phenolic OH of BHPPA with a suitable reagent like oxirane, which would lead to groups like O-CH2-CH2-OH in the place of the phenolic OH. Such a BHPPA modification should in turn yield modified “poly-BHPPA” polycondensates, which would combine the advantages of poly-BHPPA with those of aliphatic OH precursors of polyurethanes. Poly-BHPPA synthesis Hyperbranched polymers of the 4,4-bis-(4’-hydroxyphenyl)pentanoic acid (BHPPA) were synthesized successfully by the catalyzed (by dibutyltin diacetate) polycondensation of BHPPA. The products obtained were oligomers with number average molecular weight ranging from 1800 to 3400 g/mol (polymerization degree of ca. 6 to 12), displaying a first moment of functionality in the range 7 to 14. Such products were good OH precursors for the preparation of polyurethane coatings, because higher functional polymers would gel at low conversions. The analysis of the functional groups (determination of acid and hydroxyl numbers) and the 1H-NMR and the 13C-NMR spectroscopy were found to be good methods for the determination of molecular weights. The polydispersity of the poly-BHPPA products was in the range 3.5 to 6. Their degree of branching was found to be in the range 0.36 to 0.47. Poly-BHPPA containing aliphatic polyols as core monomers were also prepared successfully. Difunctional and trifunctional core monomers usually reached a full conversion of their OH groups, while the tetra- and hexafunctional core monomers were converted only to 89%. In all these products however, a considerable amount, usually even a majority, of the polymer molecules were core free. The poly-BHPPA products prepared displayed relatively high glass transition temperatures, in the range of 84°C to 114°C, obviously due to interactions between the phenol groups and to hydrogen bridging. The thermal stability of these products was also high, with decomposition occurring near 350°C (at a heating rate of 10°C / min) Kinetics investigations of the poly-BHPPA reactivity towards isocyanates The poly-BHPPA are polyphenols and were expectedly found to react significantly slower with isocyanates than aliphatic alcohols. The reactivity of poly BHPPA was also found to be somewhat lower than that of the monofunctional, low molar-mass 4 ethylphenol. Hexamethylene diisocyanate trimer, Desmodur N3300, was found to be more reactive than hexamethylene diisocyanate (HDI) or butyl isocyanate in all experiments, possibly due to a substitution effect. The substitution effect can be explained by a change of microenvironment caused by conversion of isocyanate group and OH group into urethane groups. The reactions of low-molecular-mass alcohols or phenols with low molecular weight isocyanates followed well the 2nd order kinetics, while the reactions of poly-BHPPA with isocyanates show deviations from ideal 2nd order kinetics at higher conversions. All the kinetics experiments were carried out under catalysis by dibutyltin dilaurate. This catalyst inhibits the undesired reaction of isocyanate groups with moisture. It was also found that the catalysis was necessary to reach reasonable curing times for poly-BHPPA based polyurethane networks. The uncatalyzed systems reacted extremely slowly. Preparation of polyurethane networks from poly-BHPPA The poly BHPPA products prepared were used successfully as OH functional precursors of polyurethane networks. The networks prepared contained only very low sol fractions. Acetone and also ethylene diglycol dimethylether (diglyme) were found to be good swelling solvents for the networks prepared, while methyl propyl ketone was a much poorer solvent and aromatic compounds like toluene or xylene practically did not swell the poly BHPPA based polyurethanes. The networks prepared contain a relatively high amount of cyclic bonds, 40 to 50% in the finally cured state, which is an expected result for systems with precursors of high functionality and with small distances between the functional groups. The temperature of glass transition (Tg) of the networks prepared (ranging from 68°C to 126°C) depends of the poly BHPPA precursor used: it increases with increasing molecular mass and with increasing core functionality. The choice of the isocyanate crosslinker also influences Tg: the networks made from HDI show higher Tg values, than networks made from the same poly BHPPA but crosslinked with Desmodur N3300 (Tri HDI). The urethane bonds in the networks prepared start to decompose near 140°C. The easier degradation of PU with aromatic urethane bonds is a disadvantage in comparison with aliphatic polyurethanes, whose decomposition starts at 200°C. The surfaces of polyurethane coatings prepared are smooth, displaying a roughness of ca. 20-25 nm, and relatively hydrophilic: the contact angle with water was found to be near 80°. The prepared networks are also relatively hard, possessing the Shore D hardness of 70.

The main goal of this work is design and synthesis of novel composite hydrogel-based core-shell microparticles and their application for fabrication of coatings, which provide the “inverse-switching” behaviour to the surface, namely, to become more hydrophobic in water environment. Since contact angle of heterogeneous surfaces is dependent on the nature and ratio of surface components, an increase of amount of more hydrophobic component on the surface will cause the reducing of surface wettability. It was suggested that core-shell particles having water-swellable hydrogel core and hydrophobic, but permeable for water shell when deposited on the hydrophilic substrate should increase the total amount of hydrophobic component on the surface when the cores of particles will swell in water. During the work different approaches to obtain freely dispersed and surface-immobilized core-shell particles with required structure were developed. Obtained particles were applied for preparation of coatings with ability to display “inverse-switching” behaviour. It was demonstrated that properly designed and properly prepared core-shell particles could be successfully used for creation of smart adaptive coatings having the ability to alter the surface properties upon changing of the environment.

Abstract des Vortrages: Die Wirkungstiefe einer Reibungsbeanspruchung von Werkstoffen reicht von wenigen Mikrometern bis zu etwa einem Millimeter. Die Randschicht der Werkstoffe sollte entsprechend angepasst sein. Durch Reibung beanspruchte Werkstoffe verschleißen in Abhängigkeit von den Systemeigenschaften des tribologischen Systems durch vier Elementarmechanismen, Adhäsion, Abrasion, Ermüdung und tribochemische Reaktionsschichtbildung. Das Gefüge in der Randschicht muss so eingestellt werden, dass Adhäsion, Ermüdung und tribochemische Reaktionsschichtbildung weitestgehend unterdrückt sind und der abrasive Mechanismus im Gleichgewichtszustand des Tribosystems eine minimale konstante Rate aufweist. Beschichtungen bestehen meist aus einer harten Schicht auf einem weicheren Untergrund, die bei stärkerer Beanspruchung zerstört wird. Bessere Eigenschaften sind zu erwarten, wenn in der Randschicht des Werkstoffes Veränderungen vorgenommen werden, die einen kontinuierlichen Übergang zum Grundwerkstoff bewirken. Von besonderem Interesse ist dabei das Umschmelzlegieren mit dem Elektronenstahl (EBUL). Damit lassen sich lokal Reibungskoeffizient, Verschleiß- und Korrosionswiderstand oder die thermische Leitfähigkeit durch Zulegieren von Elementen oder Dispergieren von Hartstoffpartikeln entsprechend der Beanspruchung verändern. In Studien wurde gezeigt, dass EBUL zu signifikant höheren Härten in der Randschicht führt, welche den Verschleißwiderstand erhöhen. Die Härtesteigerung kann durch den Volumenanteil der zulegierten Elemente eingestellt werden. Die Härte des umschmelzlegierten Gefüges steigt mit zunehmendem Anteil von Ausscheidungen und intermetallischen Phasen. Die Härte wird weiterhin durch die Größe und Verteilung der Ausscheidungen und Phasen bestimmt.

The main objective of this work was to manufacture and to characterize detonation nanodiamond (ND) coatings with high biocompatibility and high drug loading capability. This was achieved via the integration of functionalized NDs into standard coating systems. The examination of cell proliferation and cell differentiation supported the biological assessment of the ND-enhanced coatings. As a first step, an osteogenic peptide was covalently grafted onto oxidized NDs. Accordingly, carboxylic acid derivativ is were generated on the as-received ND surface via an optimized heat treatment. The osteogenic peptide was tethered to the oxidized ND surface using a carbodiimide crosslinking method. The multifaceted ND preparation and disaggregation facilitated the powder handling during the conjugation process. Moreover, antibiotics were physisorbed onto as-received NDs to add antimicrobial properties. The correlated surface loading of NDs was determined using various absorption spectroscopy methods such as fluorescence and ultraviolet-visible spectroscopy. Peptide-conjugated NDs and NDs with untreated surface chemistry have been immobilized on different biomaterials using liquid phase deposition techniques. Herein, polyelectrolyte multilayers (PEMs) were utilized, among others, due to their self-organization and universal applicability for numerous substrates. In order to assess the cell-material interactions, human fetal osteoblasts (hFOBs) were cultured. The hFOBs exhibited a high cell proliferation, high cell density, and sound cellular adhesion, which proves the high biocompatibility of PEMs containing NDs. The present study represents a novel and reliable strategy towards a public approved composite coating. The potential of NDs as a biocompatible delivery platform and as a coating material for biomaterials has been demonstrated. This technology will be useful for the development and optimization of next-generation drug delivery vehicles, e.g. drug-eluting coatings, as well as for biomaterials in general.:Abstract i Kurzfassung iii List of Figures v List of Tables vi Abbreviations vii 1 Introduction and Objectives 1 1.1 Scope of the Thesis 3 2 Fundamentals 9 2.1 Overview of Biomaterials 9 2.2 Surface Modification Techniques of Biomaterials 11 2.3 Cellular Response to Tailored Biomaterials 13 2.4 Essential Features of Detonation Nanodiamonds 15 2.4.1 Biomedical Applications 16 2.4.2 Chemical Functionalization Pathways 19 2.4.3 Colloidal Stability 21 3 Materials and Methods 25 3.1 Wet Chemical and High-temperature Oxidation of Detonation Nanodiamonds 26 3.2 Disaggregation of Detonation Nanodiamond Agglomerates 26 3.3 Grafting of Biomolecules onto Detonation Nanodiamonds 27 3.4 Macroscopic Surface Modification of Biomaterials 28 3.5 Characterization Techniques 30 3.5.1 Morphology 30 3.5.2 Colloidal Stability and ND Crystal Structure 30 3.5.3 ND Surface Chemistry and Surface Loading 31 3.5.4 Alkaline Phosphatase Activity of Human Mesenchymal Stem Cells 31 3.5.5 Cell Viability and Immunofluorescence Staining of Human Fetal Osteoblasts 32 4 Surface Modification of Detonation Nanodiamonds 35 4.1 Comparison of Wet Chemical and High-temperature Oxidation 35 4.1.1 Absorption Spectroscopy 35 4.1.2 Crystal Structure of Dry-oxidized NDs 37 4.2 Chemisorption of Bone Morphogenetic Protein-2 Derived Peptide 38 4.3 Physisorption of Amoxicillin 42 4.4 Conclusions 44 5 Coatings Exhibiting Detonation Nanodiamonds 47 5.1 Colloidal Stability of Aqueous ND Suspensions 47 5.1.1 ND Agglomerate Size and Zeta Potential Measurement 47 5.1.2 Influence of pH and Ion Concentration 50 5.2 Electrophoretic Deposition and Covalent Attachmen 51 5.3 Polyelectrolyte Multilayers 55 5.4 Conclusions 56 6 Biological Assessment of Detonation Nanodiamond Coatings 59 6.1 Alkaline Phosphatase Activity of Mesenchymal Stem Cells 59 6.2 Cellular Response of Osteoblasts 61 6.2.1 Cell Morphology 61 6.2.2 Cell Adhesion . 64 6.2.3 Cell Viability 66 6.3 Conclusions 68 7 Summary and Outlook 71 Acknowledgements 77 References 79 Appendix 109 List of Publications 113 / Das Hauptziel der Arbeit bestand in der Herstellung sowie der Charakterisierung von Beschichtungen aus Detonationsnanodiamanten (ND), welche eine hohe Biokompatibilität und eine hoheWirkstoffbeladbarkeit aufweisen sollten. Dieses Ziel wurde durch die Integration funktionalisierter ND in herkömmliche Beschichtungssysteme erreicht. Die biologische Beurteilung von den ND-verstärkten Beschichtungen wurde durch Untersuchungen der Zellproliferation und der Zelldifferenzierung untermauert. Im ersten Schritt wurde ein Peptid mit knochenbildenden Eigenschaften kovalent an oxidierte ND angebunden. Mittels einer optimierten Wärmebehandlung wurden Carbonsäurederivate auf der ND-Oberfläche erzeugt. Anschließend wurde das Peptid unter Verwendung eines Carbodiimid-Vernetzungsmittels an die oxidierte ND-Oberfläche angebunden. Während des Konjugationsprozesses erleichterte die facettenreiche ND-aufbereitung und -disaggregation die Pulverhandhabung. Außerdem wurden Antibiotika auf den ND adsorbiert, um antimikrobielle Eigenschaften zu erzeugen. Die entsprechende Oberflächenbeladung der ND wurde unter Verwendung verschiedener absorptionsspektroskopischer Ansätze wie Fluoreszenz- und UV/Vis-Spektroskopie bestimmt. Biofunktionale und unbehandelte ND wurden über Flüssigphasenabscheidung auf verschiedene Biomaterialien aufgebracht. Hierbei wurden unter anderem Polyelektrolyt-Mehrschichtsysteme aufgrund ihrer Selbstorganisation und universellen Anwendbarkeit auf zahlreiche Substrate eingesetzt. Um die Zellantwort auf die mehrschichtigen ND zu bewerten, wurden humane Osteoblasten (hFOB) kultiviert. Die hFOB zeigten eine hohe Zellproliferation, eine hohe Zelldichte und eine hohe Zelladhäsion, was die hohe Biokompatibilität von mehrschichtigen ND belegt. Die vorliegende Arbeit stellt eine neuartige und zuverlässige Strategie für eine allgemein anerkannte Verbundbeschichtung dar. Das Potenzial von ND als biokompatible Medikamententräger und als Beschichtungsmaterial für Biomaterialien konnte aufgezeigt werden. Die dargestellte Technologie kann für die Entwicklung und Optimierung von Medikamententrägern der nächsten Generation, z. B. in arzneimittelfreisetzenden Beschichtungen, sowie für Biomaterialien im Allgemeinen verwendet werden.:Abstract i Kurzfassung iii List of Figures v List of Tables vi Abbreviations vii 1 Introduction and Objectives 1 1.1 Scope of the Thesis 3 2 Fundamentals 9 2.1 Overview of Biomaterials 9 2.2 Surface Modification Techniques of Biomaterials 11 2.3 Cellular Response to Tailored Biomaterials 13 2.4 Essential Features of Detonation Nanodiamonds 15 2.4.1 Biomedical Applications 16 2.4.2 Chemical Functionalization Pathways 19 2.4.3 Colloidal Stability 21 3 Materials and Methods 25 3.1 Wet Chemical and High-temperature Oxidation of Detonation Nanodiamonds 26 3.2 Disaggregation of Detonation Nanodiamond Agglomerates 26 3.3 Grafting of Biomolecules onto Detonation Nanodiamonds 27 3.4 Macroscopic Surface Modification of Biomaterials 28 3.5 Characterization Techniques 30 3.5.1 Morphology 30 3.5.2 Colloidal Stability and ND Crystal Structure 30 3.5.3 ND Surface Chemistry and Surface Loading 31 3.5.4 Alkaline Phosphatase Activity of Human Mesenchymal Stem Cells 31 3.5.5 Cell Viability and Immunofluorescence Staining of Human Fetal Osteoblasts 32 4 Surface Modification of Detonation Nanodiamonds 35 4.1 Comparison of Wet Chemical and High-temperature Oxidation 35 4.1.1 Absorption Spectroscopy 35 4.1.2 Crystal Structure of Dry-oxidized NDs 37 4.2 Chemisorption of Bone Morphogenetic Protein-2 Derived Peptide 38 4.3 Physisorption of Amoxicillin 42 4.4 Conclusions 44 5 Coatings Exhibiting Detonation Nanodiamonds 47 5.1 Colloidal Stability of Aqueous ND Suspensions 47 5.1.1 ND Agglomerate Size and Zeta Potential Measurement 47 5.1.2 Influence of pH and Ion Concentration 50 5.2 Electrophoretic Deposition and Covalent Attachmen 51 5.3 Polyelectrolyte Multilayers 55 5.4 Conclusions 56 6 Biological Assessment of Detonation Nanodiamond Coatings 59 6.1 Alkaline Phosphatase Activity of Mesenchymal Stem Cells 59 6.2 Cellular Response of Osteoblasts 61 6.2.1 Cell Morphology 61 6.2.2 Cell Adhesion . 64 6.2.3 Cell Viability 66 6.3 Conclusions 68 7 Summary and Outlook 71 Acknowledgements 77 References 79 Appendix 109 List of Publications 113

The scope of this work is to fathom different possibilities to create functional coatings with polymer brushes. The immobilization of nanoparticles and enzymes is investigated, as well as the affection of their properties by the stimuli-responsiveness of the brushes. Another aspect is the coating of 3D-nanostructures by polymer brushes and the investigation of the resulting functional properties of the hybrid material. The polymer brush coatings are characterized by a variety of microscopic and spectroscopic techniques, with a special emphasis on the establishment of the combinatorial quartz crystal microbalance/spectroscopic ellipsometry technique as a tool to characterize the functional properties of the polymer brush systems insitu. The pH-responsive swelling of the polyelectrolyte brushes poly(acrylic acid) and poly(2-vinylpyridine), as well as the thermoresponsive swelling of poly(N-isopropylacryl amide) is studied in detail by this technique. Poly(2-vinylpyridine) and binary poly(N-isopropylacryl amide)-poly (2-vinylpyridine) brushes are used as templates for the insitu-synthesis of palladium and platinum nanoparticles with catalytic activity. As an example for the use of polymer brushes to immobilize enzymes, the model enzyme glucose oxidase is physically adsorbed to poly (2-vinylpyridine) and poly (acrylic acid) brushes and also covalently bound to poly (acrylic acid) brushes. In the last part of this thesis, sculptured thin films are coated with poly (acrylic acid) and poly (N-isopropylacryl amide) brushes and the swelling characteristics as well as the adsorption behavior of the model protein bovine serum albumin are investigated.

In der vorliegenden Arbeit wurde gezeigt, dass enzymresponsive Peptid-Poly(ethylenglycol)-Konjugate (Peptid-PEG-Konjugate) effizient biotransformiert und proteinresistente Beschichtungen ausbilden können. Die oberflächenspezifische Haftung eines linearen Biokonjugates auf Basis einer literaturbekannten Adhäsionsdomäne für Titandioxid-Oberflächen wurde durch Verlängerung mit einer proteolytisch spaltbaren Erkennungssequenz und einer Suppressionsdomäne temporär unterbunden. Aus einer Serie unterschiedlich modifizierter Biokonjugate wurde eine anionische Suppressionsdomäne als besonders leistungsfähige haftungsunterdrückende Einheit identifiziert. Die Prozessierung des nicht-bindenden Vorläufers mit einer spezifischen Cysteinprotease hervorgehend aus dem Tabakätzvirus (TEV Protease) bewirkte die Abtrennung der eingeführten Modifikation. Durch die Biotransformation wurden die Haftungseigenschaften der polymergebundenen Adhäsionsdomäne zurückgebildet. Das aktivierte Biokonjugat ermöglichte die nicht-kovalente PEGylierung der Metalloxid-Oberfläche. Das Konzept wurde auf divalente Peptid-PEG-Konjugate unter Verwendung verzweigter Adhäsionsdomänen und verlängerter Suppressionsdomänen übertragen. Die proteolytisch aktivierte Dimer-Beschichtung zeigte eine erhöhte Stabilität im Vergleich zum linearen Biokonjugat und demonstrierte vielversprechende Antifouling-Eigenschaften gegenüber der unspezifischen Adsorption eines Modellproteins für Serumproteine des menschlichen Blutes auf Titandioxid-Oberflächen. / The present thesis has shown that enzyme-responsive peptide-poly(ethylene glycol) (peptide-PEG) conjugates can be efficiently biotransformed to create protein-resistant coatings. The surface-specific adsorption of a linear bioconjugate is temporarily suppressed by extending a titanium dioxide adhesion domain known from literature with a proteolytically cleavable recognition site and a suitable interfering domain. From a series of differently modified bioconjugates, an anionic interfering domain was identified as particularly effective to suppress adhesive functions. The enzymatic processing of the non-binding precursor with a specific cysteine protease derived from tobacco etch virus (TEV protease) resulted in the separation of the introduced modification. The adhesive properties of the polymer-bound binding sequence were reproduced by the biotransformation process. The activated bioconjugate allowed the non-covalent PEGylation of the metal oxide surface. The concept was applied to divalent peptide-PEG conjugates using branched adhesion domains and extended interfering domains. The proteolytically activated dimer coating showed increased stability against dilution compared to the linear bioconjugate and demonstrated promising antifouling properties against the non-specific adsorption of a model protein for human blood serum proteins to titanium dioxide surfaces.

Die vorliegende Arbeit beschäftigt sich mit der Entwicklung neuer Schichtsysteme für die Realisierung biaxial texturierter hochtemperatursupraleitender Bandleiter. Bisher sind eine Vielzahl von Bandleiterarchitekturen bekannt, die sowohl durch physikalische Depositionsmethoden als auch mittels Abscheidung aus der chemischen Lösung hergestellt werden können. Während die Funktion von YBCO-Bandleitern mit Hilfe physikalischer Depositionsmethoden in den letzten Jahren demonstriert werden konnte, zeigen auf chemischem Wege deponierte Bandleiter schlechtere Eigenschaften. Seitens der Industrie besteht ein starkes Interesse, die hohen Produktionskosten, die im Hinblick auf physikalische Depositionsmethoden mit einem hohen Anlagenaufwand verbunden sind, anhand der kostengünstigen chemischen Synthese von Einzelschichten oder der gesamten Bandleiterarchitektur zu senken. Gelöst wurde diese Aufgabe innerhalb der vorliegenden Arbeit durch die Entwicklung metallorganischer Vorstufenlösungen zur Deposition von CaTiO3-, SrTiO3-Pufferschichten und supraleitender YBa2Cu3O7-Schichten.

Tribology has been recognized as a very important discipline in different branches of industry because almost every mechanical system has some moving parts. Due to the relative motion between these different mechanical parts, a variety of contacts are formed, and they are very often lubricated with oil. Environmental protection and ecological awareness are becoming increasingly important, which in turn has resulted in the shift to a low-carbon society, making water more interesting as a possible lubricant. On the one hand, water is less environmentally damaging as a lubricant than oil, but on the other hand, water has very poor lubrication properties, as its viscosity is 100 times lower than the viscosity of oil. These limitations might be overcome by appropriate surface engineering (e.g., diamond-like carbon, DLC). Tribological tests were performed in oil and water for two different contacts. Steel/steel and steel/DLC were investigated. DLC was recognized as a very promising solution, which ensures low friction and low wear. DLC was deposited on a real hydraulic part in an orbital hydraulic motor and tested under real industrial conditions. The overall efficiency of the hydraulic motor was measured.

In this paper, a simulation study is carried out for the development of concepts to optimize the tribological contact of valve plate and cylinder block in an axial piston machine in swash plate design. The valve plate/cylinder block contact is one of the three essential tribological contacts in axial piston machines. In a research project at the Institute for Fluid Power Drives and Systems (ifas), this contact is investigated by a specifically designed simulation tool. In addition, a test rig exists for the experimental investigation. With the results of simulation and experiment, it was shown before that the cylinder block is tilting to the high pressure side. Due to this movement, the gap height is not constant. In the area of minimum gap height, not only the fluid friction, but also the danger of solid body friction increases. Because of the higher friction losses in the area of minimum gap height, the temperature increase reduces the lifetime of the leaded coatings. In this paper, the results of the measurements as well as the simulation model are briefly summarized. It is followed by a simulation study of different possibilities to raise the gap height. Based on this pre-study, a first concept for the optimization of the tribological contact valve plate/cylinder block is presented and its applicability is discussed.

Textile high-performance filament yarn subjected to extremely high thermal loads can be found in various technical application fields. Besides the mechanical loads, textile fiber materials have to also satisfy high safety requirements in these applications with respect to thermal loads. Some of the main fields of application in the field of mechanical engineering are turbines, drive devices, rocket components and fire protection coatings. Textile grid-like structures are also being increasingly used in civil engineering as reinforcements (textile concretes). The design and development of textile structures for these applications demands studying and acquiring the material behavior under high thermal loads. Neither sufficient data nor standardized testing methods have been extensively achieved for evaluating the tensile characteristics of filament yarns under thermal influences. Hence, studying the thermal behavior of these yarns, which are used as input material for the reinforcing structures, is essential. The impact of the standard atmospheric condition on the oxidation behavior of the yarns, as in the case of carbon filament yarns and their influence on the physicochemical and tensile mechanical properties, have to be studied as well. This paper aims to address this issue and provides an insight into the current research about the development and realization of a novel test stand and the subsequent study of tensile mechanical behavior for textile high-performance fiber material under extreme thermal loads together with their physicochemical behavior.