Filtern
Erscheinungsjahr
Dokumenttyp
Sprache
- Englisch (121)
- Deutsch (72)
- Mehrsprachig (7)
Schlagworte
- Interface (12)
- Verbundwerkstoffe (9)
- Mechanical properties (8)
- Thermoplaste (8)
- Epoxy (7)
- Acrylamide (5)
- Adhesion (5)
- Interphase (5)
- Kristallisation (5)
- Thermoresponsive polymers (5)
- Adhäsion (4)
- Composites (4)
- Diaminopyridine (4)
- Haftung (4)
- Reibung (4)
- Self-healing (4)
- Thermoresponsive polymer (4)
- UCST-type polymer (4)
- Vesicles (4)
- Carbon fibres (3)
- Composite (3)
- Elastic properties (3)
- Ermüdung (3)
- H bonds (3)
- Interfacial shear strength (3)
- Interfacial strength (3)
- Ionic liquid (3)
- Janus dendrimers (3)
- Kristallisationskinetik (3)
- Modellrechnung (3)
- Nanoindentation (3)
- Nanotubes (3)
- Polymer (3)
- UCST-type polymers (3)
- Verstärkungsfaser (3)
- 2,6-diaminopyridine (2)
- A. Carbon fibres (2)
- Avrami (2)
- B. Interfacial strength (2)
- Biegeschwingung (2)
- Cellulose (2)
- Composite structures (2)
- Dendrimersomes (2)
- Erstarrung (2)
- Faser (2)
- Fatigue (2)
- Fluorescent polymer optical fibres (2)
- Fractography (2)
- Functional composites (2)
- Glasfaser (2)
- Glass fibre (2)
- High voltage cable accessories (2)
- Ionic conductivity (2)
- Manufacturing (2)
- Microfluidic (2)
- Morphology (2)
- Multifunctional supercapacitor (2)
- Partial discharge detection (2)
- Patch (2)
- Pull-out (2)
- Pull-out test (2)
- Push-out Test (2)
- Push-out test (2)
- Recycling (2)
- Silicone rubber (2)
- Simulation (2)
- Sphärolithe (2)
- Strength (2)
- Structural electrolyte (2)
- Thermoplast (2)
- UCST polymers (2)
- 2,6-diaminopyridine-based polymers (1)
- A. Carbon nanotubes (1)
- A. Coupling agents (1)
- A. Hybrid composites (1)
- A. Polymer-matrix composites (PMCs) (1)
- AFM/SFM (1)
- ATRP polymerization (1)
- Abbauverhalten (1)
- Acoustic emission (1)
- Adhesion promotion (1)
- Alumina (1)
- Antibacterial properties (1)
- B. Adhesion (1)
- B. Debonding (1)
- B. Interface (1)
- Bacteria (1)
- Bicontinuous morphology (1)
- Bioinspiration (1)
- Biopolymer (1)
- Boehmite nanoparticle (1)
- Brillouin (1)
- CNT (1)
- Carbon Fibers (1)
- Carbon Fibre (1)
- Carbon fibers (1)
- Carbon fiberepoxy resin laminates (1)
- Carbon fibre (1)
- Carbon fibres nanotubes interface (1)
- Carbon nanotubes (1)
- Cellulose natural fibers (1)
- Ceramic spring (1)
- Ceramic springs (1)
- Characterisation (1)
- Coating (1)
- Composires (1)
- Composite material (1)
- Composite materials (1)
- Composite recycling (1)
- Concrete (1)
- Contact angle (1)
- Cooling rate (1)
- Copper (1)
- Copper (Cu) (1)
- Copper Microstructures (1)
- Crack propagation energy (1)
- Creep (1)
- Critical energy release rate (1)
- Cryogenic (1)
- Cytoskeleton mimic (1)
- DSI (1)
- Damage (1)
- Debonding (1)
- Debonding Mechanism (1)
- Deformation behavior (1)
- Dendritic amphiphile (1)
- Dentine (1)
- Desorption (1)
- Dielektrische Analyse (1)
- Distributed fibre optic sensors (1)
- Distributed sensing (1)
- Dynamic (1)
- EDX/EDS (1)
- Electric conductivity (1)
- Electrolyte (1)
- Electrospray ionization (ESI) (1)
- Electrospray ionization polymers (1)
- Elektrische Eigenschaften (1)
- Enamel (1)
- Energy release rate (1)
- Epoxy Interphase (1)
- Epoxy Resin (1)
- Epoxy based network (1)
- Epoxy resin (1)
- Failure (1)
- Failure process (1)
- Faser-Kunststoff-Verbund (1)
- Fatigue behavior (1)
- Federkonstante (1)
- Festigkeit (1)
- Fiber (1)
- Fiber Bragg grating (1)
- Fiber properties (1)
- Fiber-matrix interface (1)
- Fiber/matrix bond (1)
- Fibre Bragg grating (1)
- Fibre reinforced plastic (1)
- Fibre-matrix adhesion (1)
- Fibre/matrix bond (1)
- Fibre/matrix bonding (1)
- Films (1)
- Finite element analysis (1)
- Fluorination (1)
- Force-distance diagram (1)
- Four-parametric (1)
- Fracture (1)
- Fracture mechanics (1)
- GFK (1)
- GFRP (1)
- Gefüllte Kunststoffe (1)
- Geometrical factors (1)
- Glas fibre reinforced polymer (1)
- Glaskapillaren (1)
- Glass Fibres (1)
- Glass fibres (1)
- Glass transition (1)
- Grafting (1)
- H-bonding monomers (1)
- H-bonds (1)
- Haftfestigkeit (1)
- Hartbearbeitung (1)
- Hierarchical Structures (1)
- Hierarchical composites (1)
- Hybrid organic-inorganic copolymers (1)
- Hydrogel (1)
- Hydrothermal Ageging (1)
- Imaging (1)
- Indentation (1)
- Indentation hardness (1)
- Instrumentierte Eindringprüfung (1)
- Interdiffusion (1)
- Interface Strength (1)
- Interfacial Strength (1)
- Intermodulation AFM (1)
- Irradiation (1)
- Keramik (1)
- Keramikfeder (1)
- Keywords: Poly(ether ether ketone) (1)
- Kratzfestigkeit (1)
- Kurzfaser (1)
- Lamellen (1)
- Langzeitstabilität (1)
- Layer topography (1)
- Light curing (1)
- Lightweighting (1)
- Luminescent probes (1)
- Längenabhängigkeit (1)
- Mapping (1)
- Matrix (1)
- Matrix adhesion (1)
- Matrix residual stress (1)
- Mechanical and thermal testing (1)
- Mechanical testing (1)
- Messmethode (1)
- Microfluidics (1)
- Micromixer (1)
- Micromixers (1)
- Microstructure (1)
- Modellrechnungen (1)
- Modulus (1)
- Multifunctional epoxy (1)
- Multifunctional epoxy resin (1)
- Nachkristallisation (1)
- Nano indentation (1)
- Nano tubes (1)
- Nanoscale Characterization (1)
- Natural (1)
- Normung (1)
- Optical backscatter reflectometry (1)
- Optical fibre (1)
- PA6.6 (1)
- PDMS (1)
- PPA (1)
- Phase transformation (1)
- Photocleavable organosilanes (1)
- Photocleavage (1)
- Photoconduction (1)
- Photopolymer composites (1)
- Phytolith (1)
- Plasma nanocoatings (1)
- Plasma polymers (1)
- Plasticity (1)
- Poly(acrylic acid) (1)
- Poly- (hydroxyethylmethacrylate) (1)
- Polymer Fibres (1)
- Polymer Matrix Composite (1)
- Polymer Matrix Composites (1)
- Polymer composite (1)
- Polymer electrolyte (1)
- Polymer matrix composites (1)
- Polymer optical fibre (1)
- Polymer-matrix composites (PMC) (1)
- Polymer-metal (1)
- Polymercoating (1)
- Polyurethane (1)
- Polyvinylpyrrolidone (PVP) (1)
- Pull-Out Behaviour (1)
- Pull-out composite materials (1)
- Pull-out tests (1)
- Pulsed laser treatment (1)
- Push-in (1)
- RAFT polymerization (1)
- Ritztest (1)
- Scherfestigkeit (1)
- Schubfestigkeit (1)
- Schädigung (1)
- Selbstheilung (1)
- Self-assembly (1)
- Sensorik (1)
- Short-beam strength (1)
- Silica fibres (1)
- Single carbon fibers (1)
- Single fiber pull-out test (1)
- Single fibre pull-out test (1)
- Spannungs-Dehnungs-Verhalten (1)
- Stiffness (1)
- Strain (1)
- Strain gauge factor (1)
- Structural health monitoring (SHM) (1)
- Supercapacitor (1)
- Superstructure (1)
- Surface (1)
- Surface area (1)
- Surface modification (1)
- Synthesis (1)
- Temperature (1)
- Temperature sensitivity (1)
- Test method (1)
- Thermal cycling (1)
- Thermo mechanical fatigue (1)
- Thermomechanics (1)
- Thermomechanik (1)
- Thermoplastic (1)
- Thermoplastic matrix (1)
- Thermoplastic prepreg (1)
- Thermoset (1)
- Thermosetting resin (1)
- Thin polymer layers (1)
- Time-dependent (1)
- Tooth wear (1)
- Transkristallisation (1)
- Unidirectional composites (1)
- Validation (1)
- Verlustfaktor (1)
- Viscoelastic (1)
- Wasserstoffspeicherung (1)
- Water Diffusion (1)
- Wetting (1)
- Work of adhesion (1)
- Zirconia (1)
- Zirconia: yttria stabilized (1)
- co-solvency in water/acohol mixture (1)
- model (1)
- multi scale testing (1)
- o-Nitrobenzyl ester (1)
- pH sensing (1)
- poly(acrylamide-co-acrylonitrile) (1)
Organisationseinheit der BAM
- 5 Werkstofftechnik (25)
- 5.3 Polymere Verbundwerkstoffe (22)
- 6 Materialchemie (9)
- 6.0 Abteilungsleitung und andere (8)
- 5.4 Multimateriale Fertigungsprozesse (6)
- 8 Zerstörungsfreie Prüfung (2)
- 4 Material und Umwelt (1)
- 4.4 Thermochemische Reststoffbehandlung und Wertstoffrückgewinnung (1)
- 5.0 Abteilungsleitung und andere (1)
- 6.7 Materialsynthese und Design (1)
Paper des Monats
- ja (1)
Eingeladener Vortrag
- nein (88)
Mikromechanik
(2003)
Bestimmung zeitabhängiger lokaler Eigenschaften von Polymeren mit der Nano-Indentationstechnik
(2009)
Single Fiber Pull-out Test
(2010)
With this presentation, the push-out technique is explained. The focus of the experimental work is on the characterization of the fiber-matrix interface of short fiber reinforced composites. The reinforcing component was glass fibers and the matrix polymer was PA6.6 and PPA.
It is demonstrated for the first time that the push-out technique ca be applied on injection molded short fiber PMC and is sensitive to the mechanical interface properties. Further studies are planned on the influence of multiple processing, the temperature and humidity.
Tooth wear induced by abrasive particles is a key process affecting dental function and life expectancy in mammals. Abrasive particles may be plant endogenous opal phytoliths, exogene wind-blown quartz dust or rain borne mineral particles ingested by mammals. Nano-indentation hardness of abrasive particles and dental tissues is a significant yet not fully established parameter of this tribological system. We provide consistent nano-indentation hardness data for some of the major antagonists in the dental tribosystem (tooth enamel, tooth dentine and opaline phytoliths from silica controlled cultivation). All indentation data were gathered from native tissues under stable and controlled conditions and thus maximize comparability to natural systems. Here we show that native (hydrated) wild boar enamel exceeds any hardness measures known for dry herbivore tooth enamel by at least 3 GPa. The native tooth enamel is not necessarily softer then environmental quartz grit, although there is little overlap. The native hardness of the tooth enamel exceeds that of any silica phytolith hardness recently published. Further, we find that native reed phytoliths equal native suine dentine in hardness, but does not exceed native suine enamel. We also find that native suine enamel is significantly harder than dry enamel and dry phytoliths are harder than native phytoliths. Our data challenge the claim that the culprit of tooth wear may be the food we chew, but suggest instead that wear may relates more to exogenous than endogenous abrasives.
Atmospheric-plasma fluorination was used to introduce fluorine functionalities onto the surface of carbon fibers without affecting their bulk properties. The interfacial adhesion between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride) (PVDF) was studied by means of direct wetting measurements and single fiber pullout tests. Measured contact angles of PVDF melt droplets on modified carbon fibers show that short exposure times of carbon fibers to atmospheric-plasma fluorination (corresponding to a degree of surface fluorination of F/C = 0.01 (1.1%)) leads to improved wettability of the fibers by PVDF melts. The apparent interfacial shear strength as a measure of practical adhesion, determined by the single-fiber pullout test, increases by 65% under optimal treatment conditions. The improved practical adhesion is not due to the formation of transcrystalline regions around the fibers or a change of the bulk matrix crystallinity or to an increased surface roughness; it seems to be due to the compatibilization of the interface caused of the atmospheric-plasma fluorination of the carbon fibers.
The interaction between direct fluorinated carbon fibres and various fluoropolymers (ethylene-chlorotrifluoroethylene, poly vinylidene fluoride, fluorinated ethylene propylene copolymer and tetrafluoroethylene-perfluoro alkoxy vinyl ether copolymer) was studied by means of direct wetting measurements between fibres and the polymer melts and single fibre pull-out tests. The results of both techniques allow the adhesion behaviour between the fibres and the matrices to be predicted. The results obtained show that a low degree of surface fluorination of carbon fibres leads to an improved wettability between the fibres and fluoropolymer melts and this is an indicator for an improved thermodynamic work of adhesion. The apparent interfacial shear strength as measure of practical adhesion, determined by the single fibre pull-out test, increases with increasing degree of surface fluorine content up to a maximum, which depends on the degree of fluorination of the matrix used. The improved interaction between the fibre and the matrix is due to an enhanced compatibility at the fibre/matrix interface.
Viscoelastic properties of the interphase in fibre reinforced polymers - measurement and simulation
(1999)
A mathematical model for the description of the overall crystallization of polymers has been developed which separates the pure geometric spreading of the semicrystalline superstructures from the increasing crystallinity inside these entities. The model uses the Avrami theory for the geometric part and a freely optional function for the increasing local crystallinity. The two functions are combined by a mathematical procedure called convolution. The free option of the local crystallinity function enables this model to permit calculation of this function, which is not accessible to direct measurement. Thus with given Avrami parameters and measured values of the time-dependent overall crystallinity, this function of the local crystallinity (secondary crystallization function) can be calculated. The model has been applied to test data produced by computer simulations.
An advanced equipment for single-fibre pull-out test designed to monitor the fracture process
(1995)
Energy based characterization of the fibre-matrix interface using the pull-out and push-in test
(1997)
An Advanced Equipment for Single-Fibre Pull-Out test designed to monitor the fracture process
(1993)
Among the strategies to produce healable thermosetting systems is their modification by the addition of thermoplastic particles. This work investigates the influence of poly(ethylene-co-methacrylic acid) (EMAA) on fibermatrix interfacial properties of a glass fiber reinforced epoxy matrix composite. Epoxy-EMAA interactions were evaluated using differential scanning calorimetry (DSC) and infrared spectroscopy. The effects of EMAA on the epoxy network formation were evidenced by changes in glass transition temperature, cure kinetics and alteration of chemical groups during cure. Interfacial shear strength (IFSS) measurements obtained by single fiber pull-out tests indicate similar interfacial properties for pure and EMAA modified epoxy. Additionally, the potential for self-healing ability of an EMAA modified epoxy was demonstrated. However, IFSS after a healing cycle for the EMAA modified epoxy was lower as compared to the pure epoxy, because of the lower fiber-EMAA interfacial shear strength. So, thermoplastic healing agents has not only to fill cracks in the matrix material, but also have to be optimized regarding its interface properties to the reinforcing fibers.
Der Vortrag widmet sich der Kratzbeständigkeit-Prüfmethoden und deren Bewertung und beschreibt Begriffe/Definitionen, Wirtschaftliche Bedeutung der Kratzbeständigkeit, Mess- und Prüfverfahren – allgemein (Anwendbarkeit, Messunsicherheit, Validierung), Mess- und Prüfverfahren – speziell die Erzeugung, Prüfverfahren von Einzel- und Vielfach-Kratzern, die Charakterisierung von Verkratzungen und eine zusammenfassende Bewertung im Einzelnen
Mechanical and microstructural characterisation of multifunctional structural power composites
(2013)
Although the inherent anisotropy of polymer composites has presented daunting technical challenges, these materials now offer engineers considerable opportunities for efficient structural design. More recently, the advent of multifunctional composites which can fulfill more than one role within a system has attracted considerable interest, providing designers with exciting opportunities to innovate. Of particular interest here are structural power composites, which simultaneously carry mechanical load whilst storing/delivering electrical energy. Although the development of these composites is highly challenging, often with conflicting constituent requirements, the STORAGE consortium has had considerable success in the development of these materials for automotive applications.
The focus of this paper is structural supercapacitors, the basic architecture of a single cell of which is shown in Fig. 1. This entails two carbon fibre woven lamina (electrodes) which sandwich a glass fibre woven lamina (separator), all of which is embedded within a multifunctional matrix (electrolyte). This architecture has been the focus of the research to date, leading to components such as that shown in Fig.1 having been fabricated. This paper reports on the mechanical properties and microstructures of the different reinforcement and matrix combinations for structural supercapacitors.
Multifunctional composites which can fulfil more than one role within a system have attracted considerable interest. This work focusses on structural supercapacitors which simultaneously carry mechanical load whilst storing/delivering electrical energy. Critical mechanical properties (in-plane shear and in-plane compression performance) of two monofunctional and four multifunctional materials were characterised, which gave an insight into the relationships between these properties, the microstructures and fracture processes. The reinforcements included baseline T300 fabric, which was then either grafted or sized with carbon nanotubes, whilst the baseline matrix was MTM57, which was blended with ionic liquid and lithium salt (two concentrations) to imbue multifunctionality. The resulting composites exhibited a high degree of matrix heterogeneity, with the ionic liquid phase preferentially forming at the fibres, resulting in poor matrix-dominated properties. However, fibre-dominated properties were not depressed. Thus, it was demonstrated that these materials can now offer weight savings over conventional monofunctional systems when under modest loading.
In recent years, carbon nanotubes (CNTs) grown on fibers have attracted a lot of interest as an additional reinforcing component in conventional fiber-reinforced composites to improve the properties of the fiber/matrix interface. Due to harsh growth conditions, the CNT-grafted fibers often exhibit degraded tensile properties. In the current study we explore an alternative approach to deliver CNTs to the fiber surface by dispersing CNTs in the fiber sizing formulation. This route takes advantage of the developed techniques for CNT dispersion in resins and introduces no damage to the fibers. We focus on unidirectional glass fiber/epoxy macro-composites where CNTs are introduced in three ways: (1) in the fiber sizing, (2) in the matrix and (3) in the fiber sizing and matrix simultaneously. Interfacial shear strength (IFSS) is investigated using single-fiber push-out microindentation. The results of the test reveal an increase of IFSS in all three cases. The maximum gain (over 90%) is achieved in the composite where CNTs are introduced solely in the fiber sizing.
In this work, a closed loop recycling process is investigated, which allows polymerised bulk thermoplastic matrix (Elium 150) from production waste (also referred to as recyclate) to be reused as additive in composite manufacturing by vacuum assisted resin infusion (VARI) of virgin Elium 150 monomer. It is shown that this process can save up to 7.5 wt% of virgin material usage in each processing cycle. At the same time, the thermal stability and stiffness of the composite increases with the proportion of recyclate introduced. Contemporarily, the shear and bending properties have also been observed to improve. Gel permeation chromatography (GPC) showed that the changes observed are due to an increase in molecular weight with the recyclate content. In particular, a correlation between the molecular weight and the shear properties of the composite was discovered using single fibre push-out tests.
The research presented here attempts to assess the potential for re-using carbon fibre (CF) fabrics recovered from recycling infusible acrylic thermoplastic carbon fibre reinforced polymer composites (CFRPs) in a universal manner, i.e. by combining with a wide variety of matrices to manufacture 2nd generation composite laminates by resin infusion. The 2nd generation composites have been compared in terms of bulk and interfacial properties against counteparts processed with virgin carbon fibre fabric infused with the same matrices. Generally, an increase in damping (tanδ) was observed in all 2nd generation composites, which can be attributed to a residual thin thermoplastic layer present on the recovered fibres. The interfacial adhesion of the 2nd generation Composites was investigated by shear tests and scanning electron micsoscopy, and also appears to be less influenced by the type of matrix.
Plasma polymers and electrospray-ionization (ESI) polymer layers are compared for most efficient adhesion promotion in carbon fiber-epoxy resin composites. The ultra-thin ESI layers (2–30 nm) of commercial poly(acrylic acid) and poly-(hydroxyethylmethacrylate) produce an significant increase of adhesion measured by single-fiber pull out tests.
However, plasma Treatment has also advantages, such as simultaneous activation of the fiber substrate. Chemical structure and composition are rather far from the regular structure of commercial polymers as deposited by ESI processing.
Characterization of the mechanical properties of interphases is essential when designing multicomponent materials such as fiber-reinforced matrices, protective coatings or multi-layered structures for integrated circuits. It can provide vital information about the durability of the finished product as a composite because failure is often initiated in the interfacial region induced by internal or external stress during fabrication or service. Nanoindentation is a powerful tool for investigating mechanical properties on the micro/nano scale. However, there are some challenges associated with conducting nanoindentation near interface regions. One main challenge is that the small thickness of the interphase region (typically 1-2µm) makes it difficult to apply several adjacent indents without overlap. Another issue is that the indentations are usually restricted by local reinforcement, and it becomes difficult to isolate the change in mechanical properties due solely to interphase formation. In this study we try to gauge the feasibility of nanoindentation for characterizing epoxy/Cu interphases. We develop a sample preparation method and optimize nanoindentation parameters in an attempt to avoid the restrictions mentioned above. Atomic force microscopy (AFM) and finite element analysis are employed as reference techniques to evaluate the effectiveness of our technique. We show the influence of preparation method and nanoindentaion parameters on measurements of interphase properties and how they relate the mentioned challenges.