Hochrein T.,German Plastics Center
Journal of Infrared, Millimeter, and Terahertz Waves | Year: 2014
Although a lot of work has already been done under the older terms “far infrared” or “sub-millimeter waves”, the term “terahertz” stands for a novel technique offering many potential applications. The latter term also represents a new generation of systems with the opportunity for coherent, time-resolved detection. In addition to the well-known technical opportunities, an historical examination of Internet usage, as well as the number of publications and patent applications, confirms ongoing interest in this technique. These activities' annual growth rate is between 9 % and 21 %. The geographical distribution shows the center of terahertz activities. A shift from the scientific to more application-oriented research can be observed. We present a survey among worldwide terahertz suppliers with special focus on the European region and the use of terahertz systems in the field of measurement and analytical applications. This reveals the current state of terahertz systems' commercial and geographical availability as well as their costs, target markets, and technical performance. Component cost distribution using the example of an optical pulsed time-domain terahertz system gives an impression of the prevailing cost structure. The predication regarding prospective market development, decreasing system costs and higher availability shows a convenient situation for potential users and interested customers. The causes are primarily increased competition and larger quantities in the future. © 2014, Springer Science+Business Media New York.
Kraus E.,German Plastics Center
Journal of Applied Polymer Science | Year: 2016
We report on the surface energy characteristics of composite materials based on low-density polyethylene with addition of bentonite and organic clay. Investigated were the surface free energy, its components and parameters by wetting methods according to Berger, spatial method, and method of nonlinear systems. The determined characteristics were carried out by the selective wetting conditions for the individual constituents of the composition, including the clay powder. The thermal, mechanical, and morphological properties of obtained composites were investigated. The possibility for predicting the surface properties of composite materials based on component-wise analysis was demonstrated. © 2016 Wiley Periodicals, Inc.
Ashkar R.,German Plastics Center
Welding and Cutting | Year: 2012
Gulf Cooperation Council (GCC) countries are reducing water losses in the region by introducing German welding standards to improve the sustainability of high-density polyethylene (HDPE) piping systems. Many users have shifted from conventional piping systems, such as ductile iron, steel, glass-reinforced plastic, to achieve this objective. SKZ, the German Plastics Center is approaching this problem by providing training, education, testing, and certification according to the internationally acknowledged German welding standards from DVS, German Welding Society and DVGW, German Technical and Scientific Association for Gas and Water. More than 500 specialists have been successfully trained at the SKZ Training Center Middle East which has been functioning from August 2008. Training courses are offered for the welding of HDPE piping systems, along with the welding of polymeric sheets and membranes.
Damodaran S.,Fraunhofer Institute for Structural Durability and System Reliability |
Schuster T.,Fraunhofer Institute for Structural Durability and System Reliability |
Rode K.,Fraunhofer Institute for Structural Durability and System Reliability |
Sanoria A.,Fraunhofer Institute for Structural Durability and System Reliability |
And 3 more authors.
Polymer Degradation and Stability | Year: 2015
The effect of hot water and chlorinated water at 95 °C on differently nucleated random polypropylene pipes was analysed with respect to the chemical changes occurring to the polymer and antioxidants (AOs). Infrared microscopy (μFT-IR) was used to monitor the loss of the AOs as well as to identify their degradation products during ageing. For the quantification of the primary AO, 1, 3, 5-Tris (3, 5-di-tert-butyl-4-hydroxybenzyl)-2, 4, 6-methylbenzene (AO-13) in a mixture with Pentaerythritol tetrakis (3-3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (AO-18) and the processing stabiliser tris(2,4-di-tert-butylphenyl) phosphate (PS-2) in PP-R, a new μFT-IR method has been developed and the results were supported by extraction → HPLC. Degradation products of phenolic AOs were profiled for the first time across the pipe wall using μFT-IR. Time and space resolved content of AO-18 and AO-13 left in the pipes with time was quantified. For both ageing conditions, AO-18 and AO-13 exhibited a bilateral loss from the wall of PP-R1 whereas in PP-R2, the loss was mainly unidirectional. Oxidative induction time (OIT) measurements of mechanically prepared samples across the pipe wall also validate the bilateral and unidirectional loss profiles of AOs. The loss in average molar mass of the polymer as a result of chain scission was analysed by gel permeation chromatography. The linear relations drawn for molar mass against the relative content of AOs explain that the deterioration of the pipes was accelerated with chlorinated water. From the substantial differences in the AO loss coefficients which were calculated using μFT-IR, it can be speculated that nucleation of the PP-R exerts an influence on the depletion of AOs. © 2014 Elsevier Ltd.
Stoehr N.,German Plastics Center |
Baudrit B.,German Plastics Center |
Haberstroh E.,RWTH Aachen |
Nase M.,Hof University of Applied Sciences |
And 2 more authors.
Journal of Applied Polymer Science | Year: 2014
The objectives of the presented work were to investigate films based on polylactic acid (PLA) and polyethylene glycol (PEG) in order to improve ductility and weldability of PLA films. The effect of plasticizer amount on the thermal, rheological, and mechanical properties of PLA plasticized films was investigated. The PEG content does affect the glass transition and the cold crystallization temperature of PLA in blends, while the melting temperature was not affected by the addition of PEG. The complex viscosity of the neat PLA granules and of plasticized films showed strong temperature and angular velocity dependence. The Young's modulus and tensile strength of plasticized films were improved with increasing plasticizer concentration, while the elongation at break stays rather constant. Plasticized PLA films were furthermore heat welded. These investigations showed that plasticized PLA films can be welded by heat welding. The obtained weld strength is strongly depending on the PEG amount as well as on selected welding parameters. © 2014 Wiley Periodicals, Inc.