Liquid crystalline polymers chemistry

Plate, N.A. (ed.) (1988) Liquid Crystalline Polymers, Chemistry, Moscow (in Russian). 

Cser, F., Relationship between chemistry and properties of liquid crystalline polymers, Mater. Forum, 14, 81-91 (1990). 

Felix, A.M. Site-specific poly(ethylene glycol)ylation of peptides, in "Poly(ethylene glycol) Chemistry and Biological Applications" (J.M. Harris and S. Zalipsky, Eds.) ACS symposium Series 680, 218-238 (1997). American Chemical Society, Washington DC. Gallot, B. "Comb-like and block liquid crystalline polymers for biological applications". Prog. Polym. Sci. 21(6), 1035-1088 (1996). 

Introduction of ring-opening metathesis as a versatile polymerisation technique (ROMP) by Chauvin and Herisson Nobel Prize Chemistry to Paul J. Flory for his fundamental achievements, both theoretical and experimental, in the physical chemistry of the macromolecules Fully aromatic polyamides developed Aramids, being lyotropic liquid crystalline polymers of high strength, due to extended molecular chains (Morgan and Kwolek)... 

Liquid crystalline polymers (LCPs) have gained attraction as materials with interesting optical, mechanical and rheological properties [3-7]. This review summarizes research on thermotropic liquid crystalhne polymers synthesized by metathesis routes, as this chemistry has proven to be a versatile way to build up well-defined polymer architectures [8]. Recent results promise to ejq)and the possible uses of these methods. 

Some polymers manifest liquid crystalline ordering, which does not have the full long-range three-dimensional periodicity of crystallinity but is far more ordered than amorphicity. Since many excellent books and articles have been published on such polymers and the author does not have much that is new to add to this background information, very little will be said about polymer liquid crystallinity in this book. Van Krevelen [3] has reviewed liquid crystallinity in polymers in a readable manner and discussed its effects on properties for which quantitative structure-property relationships are available. Adams et al [41] have published a valuable compendium of articles covering the theory, synthesis, physical chemistry, processing and properties of liquid crystalline polymers. Woodward [42] has discussed and illustrated liquid crystallinity in polymers with many beautiful micrographs. 

S. L. Kwolek, a woman scientist of DuPont, invented the liquid crystal aromatic polyamides which eventually paved the way to the first commercial liquid crystalline polymer product—poly-p-phenyleneterephthalamide under the trade name Kevlar. She recently recalled, When I dissolved the PBA (poly-p-aminobenzamide) polymer at 10% concentration in tetram-ethylurea with 6.5% LiCl, the solution was unusually fluid, turbid, stir-opalescent, and butter-milk-like in appearance. The fiber that was spun turned out to be extremely strong with a modulus of 430 gpd This discovery in 1964 remains a milestone of this field. In recognition of her contribution, the American Society of Chemistry Industry awarded Kwolek the 1997 Perkin Medal. 

This review introduces the method of active ester mtheris, and discusses its application to the preparation of a variety erf specialty polymers, including amphiphilic gels, graft copolymers, and side chain reactive and liquid crystalline polymers. The polymerization and copolymerization of activated acrylates by solution and suspension techniques are discussed, and polymer properties such as comonomer distribution, molecular weights, C-NMR spectra and gel morphology are reviewed. Potential applications of these polymers are also highlighted, and the versatility of active ester synthesis as a new dimension of creativity in macromolecular chemistry is emphasized. 

Visakh P. M. (MSc, MPhil) is a Research FeUow at the School of Chemical Science Mahatma Gandhi University. He edited 2 books with Sabu Thomas from Wiley and more than 8 books in press, (from Wiley, Springer, American Chemical Society and Royal Society of Chemistry and Elsevier) He has been invited as a visiting student in Italy (2009, 2012), Argentina (2010) Sweden (2010, 2011, 2012), Switzerland (2010), Spain (2011, 2012), Slovenia (2011), France (2011), Belgium (2012), and Austria (2012) for his research work and he published more than 5 publications and more than 5 book chapters. He has attended and presented more than 25 conferences. His research interests include polymer nanocomposites, bio-nanocomposites, mbber based nanocomposites, fire retardant polymers and liquid crystalline polymers. 

Argon, A. S. (2001) Modeling of polymer glasses deformation, in Encyclopedia of Materials Science and Technology, edited by Buschow, K. H. J., Cahn, R. W., Flemings, M. C., Ilschner, B., Kramer, E. J., Mahajan, S., and Veyssiere, P., vol. 5, Polymers and Materials Chemistry, edited by Kramer E. J., Section 5.2, Amorphous and liquid crystalline polymers, edited by Windle A. H., Amsterdam Elsevier, pp. 5712-5724. 

K.-Y. Hsu, T.-C. Chang, and C.-H. Li, Studies on thermotropic liquid-crystalline polymers Part X. Synthesis and properties of crossUnkable aromatic copoly(ester)s containing conjugated double bonds. Journal of Polymer Science Part A Polymer Chemistry, 31, 971 (1993). 

Al-Itavi Kh, I., Frenkin, E. I., Kotova, E. V, Bondarenko, G. N., Shklyaruk, B. F., Kuleznev, V. N., Dreval, V. E., Antipov, E. M. (2000). Influence of high pressure on structure and thermophysical properties of mixes of polyethyleneterephthalate with liquid-crystalline polymer. In Abstracts of the 2-nd Russian Kargin Symposium Chemistry and physics ofpolymers in the beginning of the 21 century Chemogolovka, Part 1-1/13 [in Russian]. 

Kiefer, R., Application of ferroelectric liquid crystalline polymers, in Ferroelectric Polymers Chemistry, Physics, and Applications (H. S. Nalwa, ed.), Marcel Dekker, New York, 1995, pp. 815-880. 

Dow Chemical developed liquid crystalline polymers (LCP) based on diglycidyl ether of 4-4 -dihydroxy-o -methylstilbene in the 1980s (62,63). Liquid crystal thermoplastics and thermosets based on this novel chemistry showed excellent combinations of thermal, mechanical, and chemical properties, imachievable with traditional epoxies. However, commercialization of these products has not materialized. 

Chemistry and physics of liquid-crystalline polymers are discussed in Chapter 1.10 by Valery P. Shibaev. The main attention is paid to the design of liquid-crystalline polymer materials with usefid photochromic, electrooptical, and optoelectronic properties. 

More recently, ring opening metathesis polymerization (ROMP) has been used to prepare telechelic liquid crystalline polymers that carry azide end groups which can be crosslinked with a triacetylene species using the well known copper catalyzed click chemistry [22]. 

Aromatic polyamide fibers are produced by spinning liquid crystalline polymer solutions of PPTA-sulfuric acid dopes into a water coagulation bath [414], resulting in the formation of a crystalline fiber with a surface skin. Variations in the structure produced by annealing at elevated temperature are known to increase the fiber modulus due to a more perfect alignment of the molecules [472]. The chemistry and physics of the aromatic polyamide fibers have been reviewed [419]. 

An interesting area, which involves chiral liquid crystal properties, is that of temperature sensors, used, for example, in the diagnosis of skin cancer, as well as in peripheral blood circulation problems. Another application in the medical field is represented by nematic elastomer films or fibers of liquid crystalline polymers with mesogene in the side chain, that can be used in the manufacture of muscle prosthesis [28]. To optimize their performance for different applications, the current knowledge on the relationship between the structure and properties of liquid crystals should be extended. In addition to further development of liquid crystals and their applications, the liquid crystal theories represent a sound basis for other areas of interest. For example, liquid crystals can be used as model compounds for the study of molecular interactions and of their effects on self-organization in supramolecular chemistry. 

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