Liquid Crystalline Derivatives

In the same way, also the properties of a biodegradable polymer can be improved by blending it with fiber materials. However, if the blended fiber is not biodegradable, recycling becomes difficult, resulting in an increased burden on the environment (20). 

Compositions from PLA, which is a biodegradable non-Uquid-crystalline pol mer, and a biodegradable liquid crystalline pol5mer have been described. The liquid crystalline pol5mer may result in an oriented pol5mer molecule structure into a molded article which improves the mechanical strength of a molded article. 

Biodegradable liquid crystalline polymers derived from cellu-losics have been described (21,22). Such polymers include also the butyric acid ester of hydroxyethyl cellulose, the butyl ether of hy-droxypropyl cellulose, and cellulose butyl ether (20). This type of liquid crystalline polymer can be derived from waste paper. The butyric acid ester is prepared as follows (20)  

The polymer was dissolved quickly. Under these conditions, the reaction was continued further for 5 h. After the reaction, the reaction mixture 

The obtained polymer (Ma, 351 D) was confirmed to be the intended substance by infrared spectroscopy and nuclear magnetic-resonance spectroscopy and found to have a liquid crystal transition temperature of 135°C by thermal analysis. 

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Ionic LCs are interesting systems because they combine the properties of LCs with those of ionic liquids. Although alkali metal soaps were among the first thermotropic LCs to be systematically studied, ionic liquid crystalline derivatives have been reported less frequently than those based on neutral molecular and macromolecular species [39]. When the halide of [AuX(CNR)] complexes is substituted by a second isocyanide, ionic complexes [Au(CNR)2][Y] [R = C6H40C H2 + i (27a),... 

Coco, S., Cordobilla, C., Dominguez, C. and Espinet, P. (2008) Luminescent gold(I) metallo-adds and their hydrogen bonded supramolecular liquid crystalline derivative s with decyloxystilbazole as hydrogen acceptor. Dalton Transactions, 48,6894—6900. 

Scheme 55 Liquid crystalline derivative 107 of dibenzo[18]crown-6 stabilized by internal hydrogen bonds...

Oligomeric phenylacetylene liquid crystalline derivatives capable of exhibiting a biaxial liquid crystal phase have been prepared. When these agents were functionalized with the polymerizable group 4-(4-acryloyloxybutyloxy)benzoic acid and then coated onto an alignment film and polymerized. An optically anisotropic retardation film was produced. 

Cinnamic acid liquid crystalline derivatives, (IV), capable of exhibiting a biaxial liquid crystal phase were also prepared by the author [1] and used as a component in retardation films. 

In a different approach, Bruce and coworkers 210) described the preparation of liquid-crystalline derivatives of a N,C,N-Pt (II) Imninophore (Fig. 18). Interestingly, they foimd that emission in the liquid-crystal phase is characteristic of the monomeric complex, while excimer-like emission normally characterizes nonliquid-crystalline analogues. They showed that the emission of pure films is responsive to both method of preparation and tribological stimulation so that it is possible to switch in a controllable manner between monomer- and excimer-like states. 

Bisoyi, H. K. and Kumar, S. 2007. Microwave-assisted synthesis of rufigallol and its novel room-temperature liquid crystalline derivatives. Tetrahedron Lett. 48 4399-4402. 

Sienkowska MJ, Monobe H, Kaszynski P, Shimizu Y. Photoconductivity of liquid crystalline derivatives of pyrene and carbazole. J Mater Chem 2007 17 1392-8. 

Investigation of liquid crystalline derivatives of boron clusters follows three general paths (1) comparative studies of the ring effect on properties in series of isostructural mesogens, (2) behavior of homologous series, and (3) studies of mesogens with unique structures. The first two types of... 

Reaction of a phthalonitrile with a Grignard reagent leads to a phthalocyanine analogue in which one of the meso nitrogens is replaced by carbon - the so-called tetraben-zotriazaporphyrins [208, 209]. Leznoff and coworkers [210] have used this reaction to prepare a discotic liquid crystalline derivative (Scheme 54). Compound 47 forms a... 

Liquid crystalline derivatives of the polysaccharide cellulose are characterized by wormlike chains with modest persistence lengths in the order of around ten nanometers [175] and modest axial ratios [166,270]. When the lyotropic liquid crystallinity of hydroxypropyl cellulose was first discovered [251], it was... 

Almeida PL, Knndu S, Beja D, Fonseca J, Figueirinhas JL, Godinho MH (2009a) Eleformation of isotropic and anisotropic liquid droplets dispersed in a cellulose liquid crystalline derivative. CeUulose 16(3) 427-434... 

The first liquid crystalline derivatives of HAT were reported by Bushby and coworkers [90-92]. They prepared several hexaphenyl-substituted HAT derivatives 48 with different peripheral chains as shown in Scheme 4.13. It is worth noting that some non-mesomorphic HAT derivatives when mixed with other discotic liquid crystals, exhibit stable columnar phases due to complimentary polytopic interactions [90, 91],... 

K. Record charge carrier mobility in a room-temperature discotic liquid-crystalline derivative of hexabenzocoronene. Adv. Mater. 11(17), 1469-1472 (1999)... 

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