ISSN:
0887-624X
Keywords:
silphenylene-siloxane polymers
;
side chain liquid crystalline polymers
;
liquid crystalline polymers
;
mesogenic group effects
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Side-chain liquid crystalline (SCLC) silphenylene-siloxane polymers with a phenyl benzoate mesogenic group and polymethylene spacers were prepared and characterized, and their properties were compared with those of equivalent SCLC polymers, SCLCPs, with a biphenyl mesogenic group. With identical spacers and terminal substituents, the melting temperatures of the former were much lower, but the isotropization temperatures were lowered to a lesser extent, than those of the latter, and, consequently, a more thermally stable nematic phase was obtained for the former. Both types of SCLCPs formed nematic phases, while polymethylsiloxanes with the same side-chain mesogens exhibited smectic phases with wider temperature ranges. The lower thermal stability of the mesophases in the silphenylene-siloxane SCLCPs compared to those of the SCLC polymethylsiloxanes can be attributed to both the rigidity of the backbone and the greater separation of the side-chains along the main chains of the former.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1992.080300510
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