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PO: Polymerphysik
PO 12: Poster: Flüssigkristalline Polymere
PO 12.3: Poster
Dienstag, 2. März 1999, 14:00–16:00, Foyer
Dielectric Relaxation Studies on Side Chain Liquid Crystal Polymers: Copolymers from Bis[(4’-cyanobiphenyl-4-yl)oxy-9-alkyl]norborn-5-ene-2,3-dicarboxylates and Octene — •A. Kastner1, I. Alig1, A. Wewerka2, and F. Stelzer2 — 1Deutsches Kunststoff-Institut, Schloßgartenstr. 6, 64289 Darmstadt — 2Institut für Chemische Technologie organischer Stoffe,
The influence of flexible octene in a rigid norbornene backbone on the molecular dynamics in oriented and non-oriented side-chain liquid-crystalline polymers and its dependence on the weight concentration are reported. A series of statistical copolymers containing different fractions of octene was studied by calorimetric and frequency- and temperature-dependent dielectric measurements. The measured dielectric permittivity was fitted in the frequency domain using the Havriliak-Negami function. Two relaxation processes could be resolved in the liquid crystalline phases respectively, which were related to the moabsolute polarization is reduced by reduction of the number of mesogenes.tion of the side chain δ−process and to rearrangements of the main chain α−process. Near the phase transition from the liquid crystalline phase to the isotropic stage both processes were found to coexist which indicate two phases. The octene component results in higher chain mobility related to a better polarizability of the sample, whereas the absolute polarization is lessened by reduction of the number of mesogens.