Authors Tsuwi, J. ; Appelhans, D. ; Zschoche, St. ; Zhuang, R.-C. ; Friedel, P. ; Häußler, L. ; Voit, B. ; Kremer, F.
Title Molecular dynamics in fluorinated side-chain maleimide copolymers as studied by broadband dielectric spectroscopy
Date 20.10.2005
Number 12802
Abstract A series of alternating maleimide (MI) copolymers with fluorinated side chains have been investigated using broadband dielectric spectroscopy. The side chains consist of fluoroalkane (–C x F2x+1, x=1, 7, 9) end groups connected to the main chain via methylene spacers. The experiments were carried out in a frequency range of 0.1 Hz to 10 MHz and at temperatures between 120 K and 500 K. The fluorinated MI copolymers show a fast sub-T g (ß) relaxation characterized by an Arrhenius-type temperature dependence with activation energy in the range of 30–37 kJ/mol. Two more processes (a and d-like) are observed, corresponding to independent relaxations of the main chain and the fluoroalkane domains respectively. For shorter side chains, the d-like process is not observed but instead another relaxation process, a S , occurs at temperatures higher than either the a and d-like processes. When compared with unfluorinated MI copolymers, the fluorinated MI copolymers show the d-like process and a slower ß-relaxation unlike their unfluorinated counterparts. A model to explain the molecular origin of the four processes is proposed, supplemented by differential scanning calorimetry and published WAXS/SAXS data.
Publisher Colloid and Polymer Science
Citation Colloid and Polymer Science 283 (2005) 1321-1333
Tags dielectric spectroscopy molecular dynamics microphase separated fluoropolymers maleimide copolymer perfluorinated end-groups carbosilane dendrimers surface-properties block-copolymers relaxation polymers polyesters viscosity behavior glasses

Back to list