Thermotropic Phase Behavior of a Liquid-Crystalline Poly(ether ester) Derived from Hydroxydibenzoic Acid, 2-Methyl-1,3-propanediol andR-1,3-Butanediol
作者： Juan P. Fernández-Blázquez , Antonio Bello , Ernesto Pérez
关键词: Differential scanning calorimetry 、 Phase transition 、 Polymer 、 Polymer chemistry 、 Glass transition 、 Materials science 、 Amorphous solid 、 Thermotropic crystal 、 Mesophase 、 Ether 、 Physical and Theoretical Chemistry 、 Organic chemistry 、 Materials Chemistry 、 Polymers and Plastics 、 Condensed matter physics
摘要: The thermotropic phase behavior of a liquid-crystalline poly(ether ester) derived from 4'-hydroxybiphenyl-4-carboxylic acid and two different spacer diols (2-methyl-1,3-propanediol R-1,3-butanediol) has been analyzed by differential scanning calorimetry, real time synchrotron X-ray diffraction solid-state 13 C NMR. It found that the polymer develops smectic mesophase presents order inside layers. This slow rate formation, in such way it is possible to obtain either an amorphous glass or glass. These phases exhibit independent transition temperatures: 95 °C for one 85 mesophase. diffractogram this shows clear diffractions wide-angle region long spacing (of low intensity) small-angle region. All those features are characteristic intermediate order, presumably type SmI, contrast low-ordered SmC alt reported racemic polymer. Thus, chirality spacer, which provides structural regularity, makes easier packing chains, so more ordered obtained. In addition, both NMR line shapes value T H 1ρ practically same quenched annealed samples, indicating "ordered" obtained annealing not three-dimensional crystal, thus confirming its assignment as mesophase, with considerable degree conformational disorder.
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