Chemistry Reference
In-Depth Information
All polymers were obtained by means of high-temperature acceptor-
free polycondensation of terephthaloyl-bis(
n
-oxybenzoylchloride) with
bis-4-oxybenzoyl derivatives of corresponding polyethylene glycols in
solutions of high-boiling dissolvent in current inert gas. Copolyesters with
mesogenic groups, extended up to 5 phenylene cycles and up to 15-17
oxyethylene links, are able to form the structure of nematic type.
Polymers can also form the systems of smectic type [126]. The studied
in Ref. [127] was the mesomorphic structure of polymer with extended
group polyethylene glycol-1000-terephthaloyl-bis-4-oxybenzoyl-bis-4′-
oxybenzoyl-bis-4′′-oxybenzoate:
This polymer (of formula R=CH
2
CH
2
(OCH
2
CH
2
)
18-20
) was synthe-
sized by means of high-temperature acceptor-free polycondensation of
terephthaloyl-bis-4-oxybenzoate with bis-(4-oxybenzoyl-4′-oxybenzoyl)
derivative polyethylene glycol-1000 in the environment of bisphenylox-
ide [128]. The X-ray diffraction pattern revealed that the regularity of
layered order weakened with rising temperature while ordering between
mesogenic groups in edge direction kept the same. That type of specific
liquid-crystal state in named polymer formed because of melting of layers
including flexible oxyethylene decouplings at keeping of the ordering in
transversal direction between mesogenic groups.
The Ref. [129] was devoted to the study of the molecular mobility of
polymer, which formed mesophase of smectic type in temperature range
223-298
°
С. Selectively deuterated polymers were synthesized to study the dy-
namics of different fragments of polymer in focus. That polymer was found to
have several coexisting types of motion of mesogenic fragment and decoupling
at the same temperature. There were massive vibration of phenylene cycles
with varying amplitude and theoretically predicted movements of polymeth-
ylene chains [130]: trans-gosh-isomerization and translation motions involving
many bonds. Such coexistence was determined by the phase microheterogene-
ity of polymers investigated.
The process of polycondensation of terephthaloyl-bis(
n
-oxybenzoyl-
chloride) with decamethyleneglycol resulting in liquid-crystal polyester
was studied in Ref. [131]. The monomers containing groups of complex
