Thermal behavior and structure of liquid-crystalline aromatic-aliphatic polyester/poly(tetramethylene oxide) block copolymers
作者:
T. Takahashi,
F. Nagata,
期刊:
Journal of Macromolecular Science, Part B
(Taylor Available online 1991)
卷期:
Volume 30,
issue 1-2
页码: 25-39
ISSN:0022-2348
年代: 1991
DOI:10.1080/00222349108245781
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The thermal behavior and structure of poly(hexamethylenep,p′-biben-zoate) (BB-6)/poly(tetramethyleneoxide) (PTMO) block copolymers (BB-6/PTMO) were studied using differential scanning calorimetry, polarizing optical microscopy, and wide-angle and small-angle x-ray diffractometry. As the PTMO fraction increases, BB-6 liquid crystallinity decreased and two transition temperatures [Tc→M (crystal-mesophase) andTm→i (mesophase-isotropic melt)] move to lower temperatures. BB-6/PTMO containing less than 20 mol% of PTMO retains liquid crystallinity. The isotropic melt-mesophase transition exotherm of BB-6/PTMO in the cooling process moves to lower temperature with increasing PTMO. Contrary to the isotropic melt-mesophase transition, the mesophase-crystal transition exotherm moves to higher temperature, indicating that PTMO segments favor the molecular mobility of BB-6 segments. As the mole fraction of BB-6 increases, the texture indicative of the smectic liquid crystal is gradually disorganized. BB-6/PTMO containing more than 30 mol% of PTMO no longer forms the texture indicative of smectic liquid crystals.
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