Search results for " COMPOSITES"
showing 10 items of 1620 documents
Spark Plasma Sintering tool design for preparing alumina-based Functionally Graded Materials
2016
Abstract A way to produce Functionally Graded Materials (FGM) is by means of Spark Plasma Sintering (SPS) and specifically designated tools. These new tools permit a current density modulation and therefore a temperature variation along the z-axis. The key feature relies on a varying die section. FEM modelling has given the suitable range of die dimensions between the top and the bottom to obtain a given temperature gradient (around 300 °C) out of roughly a 15 mm height. Experiments conducted in different configurations (with or without samples) and the measurement of the associated thermal gradient led to improvements of the mould (in particular the introduction of a counter-piston). By th…
Small-pore driven high capacitance in a hierarchical carbon via carbonization of Ni-MOF-74 at low temperatures
2016
A hierarchical porous carbon prepared via direct carbonization of Ni-MOF-74 loaded with furfuryl alcohol at 450 °C displays high specific capacitance in comparison with other MOF-derived carbons as a result of the formation of micropores smaller than 1 nm.
Electroswitching of the single-molecule magnet behaviour in an octahedral spin crossover cobalt(ii) complex with a redox-active pyridinediimine ligand
2020
Thermal-assisted spin crossover and field-induced slow magnetic relaxation coexist in the solid state for the mononuclear cobalt(II) complex with the non-innocent 2,6-bis(N-4-methoxyphenylformimidoyl)pyridine ligand. One-electron oxidation of the paramagnetic low-spin CoII ion (SCo = 1/2) to the diamagnetic low-spin CoIII ion (SCo = 0) leads to the electroswitching of the slow magnetic relaxation in acetonitrile solution.
Effective electrical conductivity of carbon nanotube–epoxy nanocomposites
2016
The electrical conductivity of carbon nanotube–epoxy composites is investigated analytically and experimentally. The theoretical predictions of the effective electrical conductivity of carbon nanotube–epoxy composites were performed by the analytical approach based on a micromechanical model of composites. The parametric analysis carried out revealed an influence of geometrical and electrical parameters of the micromechanical model on the effective electrical conductivity of carbon nanotube–epoxy nanocomposite. The nanocomposites made from the DGEBA-based and RTM6 epoxy resins filled with different weight content of Baytubes C150P and N7000 multi-walled carbon nanotubes were prepared. The …
Chemical Modification of Nitrile to Oxazoline Functionality on a Styrene-Acrylonitrile Copolymer in the Melt
1998
Oxazoline is a very interesting functionality for reactive extrusion and other applications. In this paper, we report the possibility of chemically transforming nitrile group attached to a copolymer of styrene and acrylonitrile (SAN) to oxazoline group using 2-amino-ethanol (AE). The chemical modification of SAN with AE was done in the molten state. Among various catalysts tested, zinc acetate turned out to be the most efficient. The effects of the catalyst concentration, temperature and mixing on the overall kinetics were studied. The formation of the expected oxazoline functionality was confirmed by infrared spectroscopy and by reacting with 1-naphthylacetic acid. The reaction between the…
ECS-3: A Crystalline Hybrid Organic-Inorganic Aluminosilicate with Open Porosity
2011
Mechanical, Thermomechanical and Reprocessing Behavior of Green Composites from Biodegradable Polymer and Wood Flour
2015
The rising concerns in terms of environmental protection and the search for more versatile polymer-based materials have led to an increasing interest in the use of polymer composites filled with natural organic fillers (biodegradable and/or coming from renewable resources) as a replacement for traditional mineral inorganic fillers. At the same time, the recycling of polymers is still of fundamental importance in order to optimize the utilization of available resources, reducing the environmental impact related to the life cycle of polymer-based items. Green composites from biopolymer matrix and wood flour were prepared and the investigation focused on several issues, such as the effect of r…
Three-Point Flexural Behaviour of GFRP Sandwich Composites: A Failure Map
2010
In this work, the failure mechanisms of GFRP/PVC foam core sandwich structures subjected to three-point bending are analysed. By varying the skin thickness (t ) and the span length between supports (l), experimental tests were carried out in order to find the relationship between the geometrical configuration of the sandwiches and the failure mechanism. By plotting failure mechanism on a graph of l against t , a failure map was created identifying the three typical failure mode regions of these sandwiches. The graph clearly shows the failure mode corresponding to each combination of l and t . To help optimise the use of these sandwich beams as structural elements, a theoretical failure mode…
Effect of adding wood flour to the physical properties of a biodegradable polymer
2008
Wood flour/polymer composites (WPC) gained a significant interest during the last decades, due to several advantages related to the use of a natural-organic filler rather than an inorganic-mineral one. However, most of the studies have been performed on composites based on polyolefin matrices. A further step is the use of biodegradable polymers instead of traditional ones. In this work, wood flour (WF), under the form of short fibers, with two different sizes (coarse and fine) was added to a corn starch based biodegradable polymer of the Mater-Bi family. The effect of WF size, WF content, thermal treatment on the mechanical properties was investigated. The tensile mechanical tests showed an…
Azodyed gelatin films for holographic recording
2013
Abstract In this work we present a preparation method of azo-dyed gelatin thin films for holographic recording and their photoinduced changes of optical properties. The non-toxic, commercially available and cheap ingredients were used for film preparation. The films were prepared by mixing azo-dyes with gelatin solution. The photoinduced properties of prepared films were investigated. The photoinduced dichroism and birefringence at 532 nm laser radiation were observed. The holographic recording of surface and volume gratings by 532 nm wavelength laser radiation were performed and surface relief gratings were studied with AFM. The mass transport direction in azodyed gelatin was studied.