Liquid crystalline cyclic tetramethyltetrasiloxanes containing coumarin moietiesElectronic supplementary information (ESI) available: characterisation data; textures of CS1 and CS8; table of layer spacings. See http://www.rsc.org/suppdata/jm/b3/b302857g/

2003 ◽  
Vol 13 (6) ◽  
pp. 1253 ◽  
Author(s):  
Yanqing Tian ◽  
Eiichi Akiyama ◽  
Yu Nagase
2003 ◽  
Vol 1 (4) ◽  
pp. 387-401
Author(s):  
Mihaela Prajinaru ◽  
Natalia Hurduc ◽  
Silvia Alazaroaie ◽  
Otilia Catanescu ◽  
Nicolae Hurduc

AbstractThe paper presents a study of the thermal properties of some aromatic polyethers obtained by phase trasfer catalysis technique. The polymes were synthesized starting from 1,8-dichloro-octane and various bisphenols: 4,4′-dihydroxyazobenzene, 4,4′-dihydroxydiphenyl, bisphenol A and 2,7-dihydroxynaphthalene. Molecular simulations were performed in order to obtain supplementary information concerning the chain conformation and inter-chain interactions. The presence of azobenzenic moieties induces high phase transition values, situated near the thermal stability limit. Therefore, the thermogravimetrical study of these polymers is very important for establishing the temperature limits for DSC and optical microscopy studies. All the polymers present a good thermal stability situated above the isotropization values. In these circumstances no special precautions are necessary for the characterization methods of the liquid crystalline behavior. The kinetic characteristics suggest a similar degradation mechanism by successive reactions. The inter-chain interactions do not influence the thermostability of the samples if the polar surface of the polymer is situated below a certain value.


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