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Morphology and thermal properties of liquid crystal p ‐PAEB/ n ‐propyl methacrylate copolymers
Author(s) -
Gao Jungang,
Wang Yong,
Hou Guixiang,
Liu Guodong
Publication year - 2008
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.27674
Subject(s) - copolymer , differential scanning calorimetry , materials science , liquid crystal , polymer chemistry , methacrylate , polymer , diffractometer , phase (matter) , monomer , thermotropic crystal , texture (cosmology) , chemical engineering , scanning electron microscope , composite material , organic chemistry , chemistry , liquid crystalline , thermodynamics , physics , image (mathematics) , optoelectronics , artificial intelligence , computer science , engineering
The copolymers of p ‐phenylene di{4‐[2‐(allyloxy) ethoxy]benzoate} ( p ‐PAEB) with n ‐propyl methacrylate (PMA) were synthesized. The liquid crystalline behavior and thermal properties of copolymers were studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X‐ray diffractometer (XRD), and torsional braid analysis (TBA). The results of XRD, POM, and DSC demonstrate that the phase texture of copolymers is affected by the composition of liquid crystal units in copolymers. The POM and XRD reveal that liquid crystal monomer ( p ‐PAEB) and copolymers of p ‐PAEB with PMA are all smectic phase texture. The dynamic mechanical properties of copolymers are investigated with TBA. The results indicate that the phase transition temperatures and dynamic mechanical loss peak temperature T p of copolymers are affected by the composition of copolymers and liquid crystal cross networks. The maximal mechanical loss T p is 114°C and is decreased with added PMA. The behaviors of phase transition are affected by the crosslinking density, and it is revisable for lightly crosslinking LC polymer networks, but it is nonreversible for the densely crosslinking of LC polymer networks. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008