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Liquid Crystals and their Application
Russian Journal

Zhidkie kristally i ikh prakticheskoe ispol'zovanie

Жидкие кристаллы и их практическое использование

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Rus Eng


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Zhidk. krist. ikh prakt. ispol'z. = Liq. Cryst. and their Appl., 2008, 3, 12—22.

Synthesis and Properties of Liquid Crystal Methylcyclohexasiloxane Polymers with Side Mesogenic Cyanobiphenyl Groups

N. N. Makarova, A. V. Kaznacheev, P. V. Petrovsky, I. M. Petrova

Author affiliations
A. N. Nesmeyanov Institute of Organoelement Compounds RAS
Vavilova str. 28, 119991, Moscow, Russia. 

New LC-polymers with the main cyclolinear polymethylcyclohexasiloxane chain and the side mesogen cyanobiphenyl groups from one to four, united with the main chain across aliphatic –(CH2)10- and/plus tetramethyldisiloxane spacer, were synthesized by the reaction of hydrosilylation of cyclolinear polymethyl(vinyl)cyclohexasiloxanes with 4'-cyanobiphen-4-yl-11-(tetramethyldisiloxyl)undecanoat. The influence of Carsted's and Spaier’s platinum catalysts activity in the hydrosilylation reaction of cyclolinear polymethyl(vinyl)siloxane with 4'-cyanobiphen-4-yl-11-(tetramethyldisiloxyl)undercanoat and dimethylchlorosilane on the possibility of full substitution of vinyl groups was investigated. It has been shown that Carsted’s catalyst is more active and does not lead to secondary reactions. By the DSC, optic microscopy, SAXS methods the temperatures and enthalpies of phase transitions were determined. It has been established that with the increase of the number of mesogen groups in the united LC polymer the temperature and enthalpy of all polymesomorphic transitions rise. In opposite to this the interlayer distance of LC cyclolinear polymethylsiloxanes decreased from 59,0 to 44,0 Å.

Keywords: synthesis and properties, LC-polymers, optic microscopy, method DSC, enthalpy transition

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