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Synthesis and phase behavior of chiral side‐chain liquid‐crystalline polysiloxanes containing two mesogenic groups
Author(s) -
Hu JianShe,
Zhang BaoYan,
Liu ZuoJun,
Zang BaoLing
Publication year - 2002
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.11213
Subject(s) - mesogen , differential scanning calorimetry , side chain , thermogravimetric analysis , materials science , polymer , monomer , polymer chemistry , fourier transform infrared spectroscopy , phase (matter) , glass transition , copolymer , liquid crystal , chemical engineering , organic chemistry , chemistry , composite material , liquid crystalline , thermodynamics , physics , optoelectronics , engineering
The synthesis of chiral side‐chain liquid‐crystalline polysiloxanes containing both cholesteryl undecylenate (M I ) and 4‐allyloxy‐benzoyl‐4‐( S ‐2‐ethylhexanoyl) p ‐benzenediol bisate (M II ) mesogenic side groups was examined. The chemical structures of the obtained monomers and polymers were confirmed with Fourier transform infrared spectroscopy or 1 H‐NMR techniques. The mesomorphic properties and phase behavior of the synthesized monomers and polymers were investigated with polarizing optical microscopy, differential scanning calorimetry, and thermogravimetric analysis (TGA). Copolymers IIP–IVP revealed a smectic‐A phase, and VP and VIP revealed a smectic‐A phase and a cholesteric phase. The experimental results demonstrated that the glass‐transition temperature, the clearing‐point temperature, and the mesomorphic temperature range of IIP–VIP increased with an increase in the concentration of mesogenic M I units. TGA showed that the temperatures at which 5% mass losses occurred were greater than 300°C for all the polymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2670–2676, 2002