Dielectric Relaxation Investigations in Copolyesteramide (Vectra B950) Polymer Liquid Crystal: Thermally Stimulated Polarization Current Technique

摘要

Thermally stimulated polarization currents (TSPC) in copolyesteramide (Vectra B950) polymer liquid crystal have been investigated in the temperature region 20°-250°C under different polarizing fields ranging from 0.7 to 7 kV/cm and with different heating rates. The low temperature region of the TSP current spectra shows a pronounced peak (P₁) around 30°C. This peak has been attributed to the dipolar relaxation process associated with ester group. The peak (P₂) observed around 140°C has been attributed to a combination of two relaxation processes, the dipolar and space charge relaxation processes. A steady rise in the TSP currents by several orders of magnitude is observed above 150°C. Saturation in the TSP current around 220°C reveals the presence of a relaxation process owing to the movement of large segmental groups in LC phase.View full textDownload full textKeywordsDielectric relaxations, Polymer liquid crystal, Thermally stimulated polarization currents, Vectra BRelated var addthis_config = { ui_cobrand: "Taylor & Francis Online", services_compact: "citeulike,netvibes,twitter,technorati,delicious,linkedin,facebook,stumbleupon,digg,google,more", pubid: "ra-4dff56cd6bb1830b" }; Add to shortlist Link Permalink http://dx.doi.org/10.1080/1023666X.2010.493270