Dynamic mechanical and thermal behavior of liquid-crystalline polybutadiene-diols with mesogenic groups in side chains

被引：0

作者：

Jigounov, Alexander ^{[1
]}

Sedláková, Zdeňka ^{[2
]}

Spěváček, Jiří ^{[2
]}

Ilavský, Michal ^{[1
,2
]}

机构：

[1] Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 18000 Prague 8, Czech Republic

[2] Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 16206 Prague 6, Czech Republic

来源：

European Polymer Journal | 2006年 / 42卷 / 10期

关键词：

Liquid-crystalline polybutadiene-diols (LCPBDs) with the comb-like architecture were synthesized by reaction of a LC thiol with the double bonds of telechelic HO-terminated polybutadiene (PBD). LCPBDs with various initial molar ratios of thiol to double bonds of PBD; R0; in the range from 0.15 to 1; were prepared by the radical reaction at temperature 60 °C for 48 h. The experimentally obtained degree of modification; Re; after the reaction and purification; was determined from elemental analysis - from the amount of sulphur bounded in LCPBDs; GPC and from 1H NMR spectra. The physical properties were investigated by differential scanning calorimetry and dynamic mechanical spectroscopy. With increasing Re ratio the glass transition temperature of LCPBDs; Tg; increases from ∼ - 45 °C (neat PBD) to ∼20 °C (Re ∼ 0.5). LC transition starts at Re ∼ 0.27 (the transition temperature Tm ∼ 27 °C). With increasing Re temperature Tm increases and for Re ∼ 0.5 reaches the value Tm ∼ 74 °C; at the same time also the change in enthalpy at LC transition increases. The LC transition could be detected also by the dynamic mechanical spectroscopy; especially shape and position of mechanical functions on frequency and free volume parameters strongly depend on degree of modification. © 2006 Elsevier Ltd. All rights reserved;

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摘要：

Journal article (JA)

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页码：2450 / 2457