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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Specific mold filling characteristics of highly filled phenolic injection molding compounds

Scheffler, Thomas, Englich, Sascha, Gehde, Michael 08 March 2016 (has links) (PDF)
Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.
2

Specific mold filling characteristics of highly filled phenolic injection molding compounds

Scheffler, Thomas, Englich, Sascha, Gehde, Michael January 2013 (has links)
Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.
3

Entwicklung von kontinuierlich hergestellten dünnwandigen Graphit-Polymer-Bipolarplatten für Brennstoffzellen

Stannek, Paul, Grundler, Marco, Kayser, André, Kühnemann, Lars, Karstedt, Jörg 27 May 2022 (has links)
Innerhalb des Forschungsprojekts “InduRex” sollen u.a. dünnwandige Graphit-Polymer Bipolarplatten (BPP) für Brennstoffzellen (BZ) entwickelt werden. Der Fokus liegt dabei auf hochgefüllten Compoundmaterialien und Prozesstechniken zur kontinuierlichen Herstellung dünnwandiger Folien. Dabei wird die gesamte Prozesskette, beginnend von der Auswahl der verwendeten Rohstoffe, über die Folienherstellung bis hin zur Einbringung der erforderlichen Strukturen betrachtet. Die vom „Department of Energy“ festgelegten physikalischen und chemischen Zielwerte werden auch für die Folien als Zielvorgabe gesetzt. Der Schwerpunkt der wissenschaftlichen Arbeit liegt auf einem grundlegenden Verständnis der Materialzusammensetzung und deren Zusammenhang mit den endgültigen Eigenschaften der strukturierten Bipolarplatten, sowie deren Leistung in einem Brennstoffzellenstapel. Die hergestellten Bipolarplattenfolien wurden vor einem Zelltest umfassend hinsichtlich elektrischer Widerstände, H2-Permeation, Warmformbeständigkeit u.a. charakterisiert, um den Einfluss des Produktionsprozesses auf ihre Qualität zu bewerten. / Within the research project 'InduRex', thin-walled graphite-polymer bipolar plates (BPP) for fuel cells (FC) are to be developed, among other things. The focus is on highly filled compound materials and process technologies for the continuous production of thin-walled foils. The entire process chain, starting with the selection of the raw materials used, through film production, to the insertion of the required structures, will be considered. The physical and chemical target values defined by the 'Department of Energy' are also set as targets for the films. The focus of the scientific work is on a fundamental understanding of the material composition and its relationship to the final properties of the patterned bipolar plates, as well as their performance in a fuel cell stack. The fabricated bipolar plate films were extensively characterized in terms of electrical resistances, H2 permeation, heat deflection temperature, and others prior to a cell test to evaluate the impact of the production process on their quality.

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