FU Berlin Digitale Dissertation
Vanessa Gerstung : Analysis of complex polymers by means of field-flow fractionation Analytik von komplexen Polymeren mittels der Feld-Fluss-Fraktionierung
|Abstract| |Table of Contents| |More Information|

Abstract Due to higher demands on modern polymeric materials, these substances often contain chemical heterogeneities in addition to molecular heterogeneities. In order to characterise these polymers new analytical methods beside standard techniques are necessary. The average molecular mass and its distribution represent important properties of polymers. The determination of these properties that are important for further processing and application of the polymers can be very difficult due to the complexity of polymer systems. The separation in fractions with uniform molecular and/or chemical properties can be used as an approach to solve these problems. For that purpose the principle of field-flow fractionation (FFF) can be applied. In this thesis, the application of FFF methods shall be validated and extended; the limit of the method will be discussed. This work demonstrates the ability of FFF to characterise polymers with ultra-high masses as well as compounds with varying molecular mass distributions and different chemical compositions. Accurate molecular masses can be obtained after calibration the system with standards. In addition to polymers with very high molecular mass, crosslinked polymers and gels can also be investigated by FFF. One main focus of this work is to characterise electron beam treated polyvinylchloride (PVC) foils using thermal FFF (ThFFF). Depending on the composition of the foils and on the parameter of radiation strong influences on molecular mass were shown. Molecular masses up to 109 g/mol can be detected. Styrene, acetylene and allylalcohol polymers generated by plasma initialised polymerisation have been analysed and molecular masses up to 108 g/mol were observed. PS-PI- and PS-PMMA-diblock copolymers were analysed in different solvents by ThFFF. It was possible to determine selectively the molecular mass of one single block after calibration with corresponding standards. By means of asymmetric flow field-flow fractionation (AF4), different mechanisms of polymerisation in sol-gel systems can be observed and the resulting differences in molecular mass can be detected.

Table of Contents Download the whole PhDthesis as a zip-tar file or as zip-File For download in PDF format click the chapter title Titelblatt und Inhalt Gutachter Publikationen Danksagung Inhaltsverzeichnis 1. Einleitung und Aufgabenstellung 2. Feld-Fluss-Fraktionierung 3. Kalibrierung der ThFFF und AF4 4. Charakterisierung von elektronenstrahlbehandelten PVC-Folien 5. Charakterisierung von Diblockcopolymeren 6. Charakterisierung von Plasmapolymeren 7. Charakterisierung von Sol-Gel-Materialien 8. Zusammenfassung und Ausblick 9. Experimentelle Methoden 10. Verwendete Abkürzungen und Symbole 11. Literaturverzeichnis

More Information:
Online available:	http://www.diss.fu-berlin.de/2002/117/indexe.html
Language of PhDThesis:	german
Keywords:	field-flow fractionation, polyvinylchloride foils, diblock copolymers, plasma polymers, sol-gel systems
DNB-Sachgruppe:	30 Chemie
Date of disputation:	26-Jun-2002
PhDThesis from:	Fachbereich Biologie, Chemie, Pharmazie, Freie Universität Berlin
First Referee:	Prof. Dr. Manfred Hennecke
Second Referee:	Prof. Dr. Helmut Baumgärtel
Third Referee:	Prof. Dr. Jürgen-Hinrich Fuhrhop
Contact (Author):	Vanessa.Gerstung@bam.de
Contact (Advisor):	Manfred.Hennecke@bam.de
Date created:	11-Jul-2002
Date available:	12-Jul-2002

 

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