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Dipolar motions and phase transitions in a side‐chain polysiloxane liquid crystal. A study by thermally stimulated depolarization currents
Authors:Natlia T Correia  Joaquim J Moura Ramos
Abstract:The relaxation mechanisms present in a side‐chain liquid crystalline polymer have been studied by Thermally Stimulated Depolarization Currents (t.s.d.c.), in a wide temperature range covering the glassy state, the glass transition region, and the liquid crystalline phase. The thermal sampling procedure was used to decompose the complex relaxations into its narrowly distributed components. Three relaxation mechanisms were observed in this polymer: a relaxation below the glass transition temperature that is broad and extends from ?150°C up to ?110°C, the glass transition relaxation whose maximum intensity appears at ~20°C, and a relaxation above the glass transition temperature, in the liquid crystalline phase. The attribution of these relaxations at the molecular level is discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 227–235, 1999
Keywords:glass transition  compensation  dielectric relaxation  TSC  TSDC  liquid crystal polymer
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