Ohneiser, Alexander (2011)
Kombination von Ultraschallspektroskopie und Dilatometrie zur Analyse der Strukturbildung während der Kristallisation von Polymeren unter Druck.
Technische Universität
Ph.D. Thesis, Primary publication
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Dissertation Ohneiser -
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Item Type: | Ph.D. Thesis | ||||||
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Type of entry: | Primary publication | ||||||
Title: | Kombination von Ultraschallspektroskopie und Dilatometrie zur Analyse der Strukturbildung während der Kristallisation von Polymeren unter Druck | ||||||
Language: | German | ||||||
Referees: | Alig, Priv.-Doz. I. ; Stühn, Prof. Dr. B. | ||||||
Date: | 21 May 2011 | ||||||
Place of Publication: | Darmstadt | ||||||
Date of oral examination: | 7 February 2011 | ||||||
Abstract: | Isothermal crystallization experiments of isotactic polypropylene at moderate pressure have been carried out using a new measuring cell. By a combination of pressure dilatometry and ultrasound spectroscopy it was able to measure simultaneously specific volume, longitudinal ultrasound velocity and excess attenuation coefficient during glass transition or crystallization. It was shown, that pressure dilatometry as well as ultrasound spectroscopy can be applied to analyse the crystallization process in polymers. Both methods allow detection of fast and very slow crystallization mechanisms and yield comparable results. By means of Hoffman-Lauritzen theory it was shown, that acceleration of crystal growth under the influence of pressure can be attributed to the shift of the characteristic transition temperatures. In addition to the systematic crystallization experiments the excess attenuation coefficient, which was measured during crystallization from the melt up to the semi-crystalline solid state, was analyzed. It was found, that ultrasound excess attenuation mainly arises from sound scattering at the boundaries of spherulites and because of molecular relaxation processes, which might lead back to the rigid amorphous fraction in between the crystal lamellae. |
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Uncontrolled Keywords: | Dissertation, Ultraschallspektroskopie, Polymer, Kristallisation, DKI, TU Darmstadt, Ohneiser, Alig | ||||||
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URN: | urn:nbn:de:tuda-tuprints-26050 | ||||||
Classification DDC: | 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften 500 Naturwissenschaften und Mathematik > 530 Physik 500 Naturwissenschaften und Mathematik > 540 Chemie 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
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Divisions: | 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences > Material Science > Structure Research 05 Department of Physics > Institute of Applied Physics 05 Department of Physics > Institute for condensed matter physics (2021 merged in Institute for Condensed Matter Physics) 05 Department of Physics > Institute for condensed matter physics (2021 merged in Institute for Condensed Matter Physics) > Experimental Condensed Matter Physics 07 Department of Chemistry > Fachgebiet Makromolekulare Chemie 07 Department of Chemistry > Physical Chemistry |
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Date Deposited: | 28 Jun 2011 12:09 | ||||||
Last Modified: | 08 Jul 2020 23:55 | ||||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/2605 | ||||||
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