Liquid crystal polymer synthesis

Report 91 Recent Developments in Epoxy Resins, I. Hamerton, University of Surrey. Report 118 Liquid Crystal Polymers - Synthesis, Properties and Applications, D. Coates, CRL Ltd. 

Liquid Crystal Polymers - Synthesis, Properties and Applications, D. Coates, CRL Ltd. 

The synthesis of technologically interesting ROMP materials using (233) includes the preparation of molecular wires,701 liquid-crystal polymers,702,703 chiral supports for catalysis,704 redox-active macromolecules,705 photochromic materials706 and embedded clusters of CdSe.707 Polymers... 

We are currently initiating three research projects that include (1) the synthesis of reflective liquid crystal/polymer composite films, (2) a study of microphase separation in hyperbranched block copolymers, and (3) the design and synthesis of polar organic thin films, which is the subject of this proposal. (47 words aim for 41 words)... 

In addition to the opportunities for new materials synthesis and characterization along these lines, transport properties, rheology, and processing techniques for liquid crystal polymers are essentially unexplored. Experiences with synthesis of polymer structure based on these liquid crystal templates may open up other creative avenues for template synthesis, for example, inside other crystalline structures, chlathrates, or zeolites, or on surfaces [4], Composites, alloys, or mixtures of liquid crystalline and flexible polymers may produce new materials. 

Polyphosphazenes represent a new approach to the design and synthesis of side-chain liquid crystal polymers. Polyphosphazenes are inorganic main-chain polymers consisting of alternating phosphorus-nitrogen atoms in the main chain with two substituents attached to each phosphorus atom. The top of Figure 1 shows the general structure for a side chain liquid crystal polymer a polymer... 

The two-step synthesis process shown in Figure 2 affords several possibilities for preparing new side-chain liquid crystal polymers. The polymerization process allows one to vary the molecular weight and molecular weight distribution (MWD), and potentially change the properties of the liquid crystalline state. Most of the polyphosphazenes reported in the literature, including the examples in this paper, are derived from the bulk uncatalyzed process this... 

Polyphosphazene synthesis provides additional possibilities for preparing liquid crystal polymers with different properties. As noted above, the substitution process (Figure 2) enables one to synthesize a wide variety of polymers. The phosphazene inorganic backbone Is a highly flexible polymer chain glass transition temperatures can... 

Synthesis of an acrylate-based liquid crystal polymer... 

Over the past two decades, liquid crystal polymers (LCP s) have received a considerable amount of attention in both academic and industrial laboratories. Often termed mesomorphic (meaning having "middle form"), liquid crystalline phases have a degree of order between that of the zero ordered liquid and that of the three dimensional crystal lattice. Recent reviews of liquid crystal polymers have provided a fundamental understanding of the synthesis, classification, morphology, and rheology of this unique class of materials (52-541. 

FIGURE 5.9 A representative scheme of synthesis of side-chain liquid crystal polymer of the type shown in Table 5.5. The monomer containing the mesogenic unit is first synthesized and then polymerized to obtain the liquid crystal polymer. 

The selective alkylation of biphenyl and naphthalene is also possible, and is of commercial interest because 4,4 -diisopropylbiphenyl and 2,6-diisopropyl-naphthalene are used in the synthesis of speciality chemicals, for example for application as liquid crystal polymer materials for displays. For these larger molecules, large-pore zeolites such as mordenite give the best performance for isopropylation of naphthalene, introducing shape selectivity to linear (or more linear) dialkylated products over dialkylated products. 

He XZ, Zhang BY, Meng FB, Tian M, Mu Q. Synthesis and characterizahon of chiral liquid crystal polymers containing donor-acceptor group. J Mater Sci 2010 45(l) 201-8. 

Li JL, Zhang WM, Zhao YL, F u JL. Synthesis and property of liquid crystal polymers containing photosensitive groups. Solid State Phenomena 2011 181-2. 

Topnani N, Hamplovi V, Ka par M, Novotnd V, Gorecka E. Synthesis, characterisation and functionalisahon of ZnO and TiOi nanostructures used as dopants in liquid crystal polymers. Liquid Crystals 2013 1-10. 

Lately, several papers on the synthesis of liquid-crystal polysulfones and on the production of mixes and melts of polysulfones with liquid-crystal polymers have appeared [201-205]. 

The effect of compatibility, morphology, rfieology, mechanical properties of mixes of polysulfones and liquid-crystal polymers are studied in Refs. [203-205]. There are several contributions on the methods of synthesizing of copolymers of polysulfones and polyesterketones and on the production of mixes [206-210]. The method for the synthesis of aromatie copolyestersulfoneketones proposed in Ref. [206] allows one to decrease the number of components used, to lower the demands to the concentration of moist in them and to increase the safety of the process. The method is in the interaction without aseotropoformer in envirorunent of dimethylsul-fone of bisphenols, dihaloydarylenesulfones and (or) dihaloydarylenek-etones and alkali agents in the shape of crystallohydrated of alkali metal carbonated and bicarbonates. All components used are applicable without preliminary drying. 

Davis, F. J. Gilbert, A. Mann, J. Mitchell, G. R., Liquid Crystal Elastomers Synthesis and Characterization. J. Polym. Sci., Part A Polym. Chem. 1990,28, 1455-1472. 

The final chapter by Dr Coles concerns a topic at the very forefront of active development. In the few years since their initial synthesis, side-chain liquid crystal polymers have excited interest firstly because of their response to electric and magnetic fields and thence to potential applications in areas such as information storage, which is discussed here. What has been opened up, however, is a powerful means of tailoring properties to applications by synthesis of suitable molecules. This has long been an aim of materials science and this field will surely be the source of future developments. 

Chiellini, E., Galli, G., and Cioni, F., Chiral liquid crystal polymers with potential ferroelectric properties synthesis and characterization, Ferroelectrics, 114, 223-228 (1991). 

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