Thermotropic main-chain liquid

Preparation of a Thermotropic, Main-Chain Liquid Crystalline (LC) Polyester by Interfacial Polycondensation... 

Thermotropic main chain liquid crystalline polymers, MCLCPs... 

This paper presents some of our results on the synthesis and structure of thermotropic main-chain liquid crystalline polyethers based on bis(4-hydroxy-phenoxy)-p-xylene. It also deals with two areas in the field of liquid crystalline polymers that have received only little attention, namely the dielectric relaxation (5-10 and Gedde, U.W. Liu, F. Hult, A. Gustafsson, A. Jonsson, H. Boyd, R.H. Polymer submitted) and the kinetics of isotropic-mesomorphic state transitions (11-14. 32). They are both very important for the understanding of the nature of the mesomorphic state in polymers and for the understanding of similarities and differences of physical phenomena between liquid crystalline and semi-crystalline polymers. 

Thermotropic Main-Chain Liquid Crystal Polymers... 

THERMOTROPIC MAIN-CHAIN LIQUID CRYSTAL POLYMERS... 

The first examples of thermotropic main-chain liquid crystal polymers were produced by Roviello and Sirigu in 1975 when they reacted alkyl acylchlorides with p, p dihydroxy-a,-(x -dimethylbenzalazine, giving the stmcture (I), which exhibited anisotropic fluid phases after melting. 

Guezala et al. [420] studied the viscoelastic behaviour of solutions of the thermotropic main chain liquid crystalline X7G (see Fig. 160), Le. a copolyester (M 20 kg/mol) of poly(hydroxy benzoic acid) (60%) and poly(ethylene tere-phthalate) (40%) in m-cresoi the material used is non-random with respect to chain structure and domains of poly(hydroxy benzoic acid) have been reported. Solutions were studied, varying in concentration from 2.5 to 45 wt%. Special care was taken to avoid water absorption, because in its presence degradation and/or trans terification might occur. 

H.K.F. Cheng, T. Basu, N.G. Sahoo, L. Li, S.H. Chan, Current advances in the carbon nanotube/thermotropic main-chain liquid crystalline polymer nanocomposites and their blends. Polymers 4 (2) (2012) 889-912. 

Heino, M. (1994) Blends of thermotropic main-chain liquid crystalline polymers and thermoplastics. Acta Polytechnica Scandinavica, Chemical Technology and Metallurgy Series, No. 220, 1-49 (+ 7 appended publications). 

Thermotropic, main-chain, liquid-crystalline polymers (LCPs) have attracted considerable attention as a result of their high stiffness and mechanical properties. There has been interest in combining the LCPs with other materials. In one area, LCPs are used, in relatively low concentration, to reinforce less-stiff materials. In another case, a second component is used as a solvent to increase the mobility in the LCP and form lyotropic liquid-crystalline materials. There are now two reports, from Kricheldorf s group, of blends of PCL with liquid-crystalline polyesters [156,157]. 

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