Polyesters liquid crystalline polymers

If one assumes the total production is a single 5 denier per filament (dpf) ( 20 pm in diameter) filament, the total length would be about 0.01 light years ( 10 " m) or the equivalent of about one million trips to the moon. While other polyesters are commercially produced in fiber form—poly(ethylene naphthalate) (PEN) poly(butylene terephthalate) (PBT) poly(propylene terephthalate) (PPT) and poly(lactic acid) (PLA) thermotropic polyester (liquid crystalline polymer (LCP)—these are of insignificant volume compared to PET. Hence this chapter focuses primarily on PET. 

Keywords Liquid crystalline polyester, liquid crystalline polymer blend, liquid crystalline polymer composite, hyperbranched liquid crystalline polymer, mechanical stability, thermal stability, reactive liquid crystalline polymer... 

In this class of thermoplastic polymers the polar group is directly incorporated in the main chain. Aspects of the dielectric activity of selected thermoplastics without formation of hydrogen bonds between chains (e.g., oxide polymers, polyesters, liquid crystalline polymers), are discussed in the following sections. 

Aromatic polyesters constitute an important class of main-chain liquid-crystalline polymers, but present the inconvenience of their reduced solubility and very high transition temperatures (sometimes not detected before the degradation of the sample). Their processability can be improved in several ways [2,3], e.g., reduction of the rigidity of the mesogen, lengthening of the spacer, or introduction of lateral substituents. 

Liquid crystalline polymers (LCPs), 49 melt rheology of, 52 Liquid crystalline (LC) state, 48-49 Liquid crystalline thermotropic polyesters, 20... 

Macromolecules dendritic, 285 hyperbranched, 284-286 Main-chain liquid crystalline polymers, 49 Main-chain polyester LCP mesogenic units, 50... 

In order to make polymers behave as liquid crystals it is necessary to introduce some structural rigidity. A typical polymer which has the required rigidity is poly(phenylenetetraphthalamide) (10.7). This material belongs to a class of polymer known as the aramids. Other liquid crystalline polymers are the thermotropic polyesters derived from /7-hydroxybenzoic acid, p, p -biphenol and terephthalic acid (10.8). 

Liquid crystal phases, 15 100 Liquid-crystal polyesters (LCPs), 10 191-192 20 38-39 manufacture of, 20 44-45 Liquid-crystal polymers (LCPs), 15 110 20 3, 78-86, 398. See also Liquid crystalline polymers (LCPs) advantages of, 20 81... 

While no direct evidence of liquid crystallinity in PET-BB copolymers has been reported, the high-BB-content copolymers have been shown to possess morphologies similar to those of liquid crystalline polyesters [40], and show major changes in both melt relaxation times and fiber tensile moduli, suggestive of structural organization in a frustrated liquid crystalline polymer (LCP) (Table 6.3 and Figure 6.4) [41, 42],... 

Thermotropic liquid crystalline polymers, like polyesters containing mesogenic units on the main chain, may not be described by the wormlike chain model (cf. Sect. 1.2). The present article does not consider this type of polymers. 

Jo, B. W. and Lenz, R. W. Liquid crystalline polymers, 7, thermotropic polyesters with main chain phenyl- 1,4-phenylene, 4,4 -biphenylene, and 1,1 -binaphthyl-4,4 -ylene units. Makromol. Chem. Rapid Commun. 3, 23 (1982)... 

Iimura, K., Koide, N., Ohta, R. and Takeda, M. Synthesis of thermotropic liquid crystalline polymers, 1, azoxy and azo-type polyesters. Makromol. Chemie 182, 2563 (1981)... 

Essentially, then, no new, large-volume, highly profitable fibers have been developed since the mid-1950s. Instead, the existing ones have become commodities with all the economic impact thereby implied. No major chemical engineering processes have been added, although the previously described ones have been modified to allow for spinning of liquid crystalline polymers or the formation of gel spun fibers. Research activity has been reduced and centered essentially on modifications of fiber size, shape, and properties, and many variants now are successfully marketed. Production volumes have increased enormously for nylon, polyester, and polyolefin. 

Although studies concerning main chain liquid crystalline polymers were originated by Onsager (la) and Ishihara (lb) in the late 1940 s, extensive work in this field did not really begin until the early 1970 s. Jackson and Kuhfuss (2) reported the first thermotropic polyester by modifying polyethylene terephthalate with various amounts of p-hydroxybenzoic acid (HBA). They found that the copolyester with HBA content of at least 35 mole % have opaque melts. Subsequent studies in the area of aromatic polyesters by various authors resulted in a large number of patents and publication. (3.) These polymers were all derived from unsubstituted and... 

Aliphatic-aromatic liquid-crystalline polymers, synthesis, 16-17 Aliphatic glycol polyesters experimental procedures, 17-18 properties, 17... 

High resolution solid-state NMR spectroscopy is also a very powerful method for characterizing the solid structure and the local motion of different solid polymers. We recently characterized the crystalline-noncrystalline structure for different crystalline and liquid crystalline polymers, such as polyolefins [7-12], polyesters [13-15], polyether [16], polyurethanes [17, 18] and polysaccharides, including cellulose [19-29], amylose [30, 31] and dextran [32]. On the basis of these analytical methods, we also investigated the intra- and intermolecular hydrogen bonds of PVA in both crystalline and noncrystalline regions as well as in the frozen solution state. In this chapter. 

From the beginning, poly(ester-imide)s had been developed as thermo-setting polymers. In the 1970s a development was started to use imide modification for improving the properties of thermoplastic polyesters. Later on in the patent literature liquid crystalline polymers can be found as being claimed as molding resins. 

A typical example of a thermotropic liquid crystalline polymers is the polyesters and the mesogen substituted polysiloxane. The aromatic amide, the super strength fiber known commercially as Kevlar belongs to the lyotropic liquid crystalline polymers. The other important lyotropic liquid crystalline polymers are poly(7-benzyl-L-glutamate), abbreviated as PBLG, cellulose derivatives, the tobacco mosaic virus, etc. 

On the other hand, liquid crystalline polymers applied to optical information storage has attracted great attention. The liquid crystalline polymer is applied mainly in terms of the thermo-optical effect. The backbone of liquid crystalline polymer can be polysiloxane, polyacrylate, or polyesters. In order to enhance the absorption coefficient for the writing laser beam, the dyes may be either dissolved into the liquid crystalline polymer in the guest-host model or attached to the backbone of the liquid crystalline polymer to form a copolymer. The nematic, cholesteric and smectic liquid crystalline polymers are all be able to be utilized in optical information storage. 

LCP liquid crystalline polymer (polyester TBAB tetrabutylammonium bromide... 

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