Liquid crystal polymer advantages

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... 

A number of other characteristics are required in order to ensure a viable polymeric conductor. Chain orientation is needed to enhance the conducting properties of a polymeric material, especially the intermolecular conduction (i.e., conduction of current from one polymer molecule to another). This is a problem with many of the polymers that are amorphous and show poor orientation. For moderately crystalline or oriented polymers, there is the possibility of achieving the required orientation by mechanical stretching. Liquid crystal polymers would be especially advantageous for electrical conduction because of the high degree of chain orientation that can be achieved. A problem encountered with some doped polymers is a lack of stability. These materials are either oxidants or reductants relative to other compounds, especially water and oxygen. 

Liquid crystal polymers (LCPs) have been a source of considerable interest for some time, as they have been shown to offer particular advantages in terms of their processability and physical properties which make them attractive in a wide range of engineering applications.346 Serrano and his colleagues have reviewed metallomesogenic polymers, including the liquid crystalline properties of several of the platinum poly-yndiyl polymers described above.85,86... 

Despite the apparent advantages of such a technique only very few references are found in the literature. This is surprising in view of the very large number of publications in recent years on liquid crystal polymers and of course also on low molecular weight liquid crystals. We wish here to illustrate this thermo-optical analysis (70A) as a tool for characterization of liquid crystal polymers. 

A new class of liquid crystal/polymer network composite with very small amounts of polymer network (3 Wt%) is described. These composites are formed by photopolymerization of the monomers in-situ from a solution of monomer dissolved in low-molar-mass liquid crystals. Several techniques have proven useful to characterize these polymer networks. This review describes polymer network structure and its influence on electro-optic behavior of liquid crystals. Structural formation in these composites begins with the phase separation of polymer micronetworks, which aggregate initially by reaction-limited, and then by diffusion-limited modes. The morphology can be manipulated advantageously by controlling the crossover condition between such modes, the order of the monomer solution prior to photopolymerization, and the molecular structure of monomers or comonomers. 

Electro-Optic Properties of Polymer Stabilized Liquid Crystals. Polymer networks have been used to stabilize many of the liquid crystal display states in various types of displays quite advantageously. In this section, we present some recent work on correlating the material properties of the liquid crystal/polymer network composite to the electro-optic properties of the flat-panel displays specifically cholesteric texture displays (75) and simple nematic birefringent type displays (7(5). 

Due to the particular properties shown by liquid crystal polymer blends, they can be considered for several applications. These materials present excellent moldability and dielectric properties, low coefficient of thermal expansion and good thermal stability [89]. In this way, they can be advantageously used in electronic devices. The use of these materials as polymer electrolytes for batteries was also reported [90]. Automotive and commercial aircraft are other areas in which liquid crystal polymer blends may find application due to their excellent processability, high use temperature, good fatigue resistance, and high modulus/strength [91]. 

The increasing interest in liquid crystal polymer blends arises not only from the academic field, but also from industries focusing on innovation. Despite the higher cost of liquid crystal polymers, blending them with traditional thermoplastics results in some very competitive advantages compared to ordinary materials. The unique properties of the liquid crystal polymer blends make them not only remarkable objects for academic investigation, but also extremely versatile soft materials for industry. 

Experimentally the attention has been attracted principally by the absorption [3] for which the anisotropy is easily observed. Only recently, detailed studies of the velocity anisotropy were published [4] in the case of a polymer liquid crystal. The advantage of a polymer is that the relaxation time is high such that at 1 Mhz the velocity anisotropy is almost 1%, The disadvantage is that this anisotropy is already almost independent of the frequency. 

The industrial development of thermotropic liquid crystal polymer (LCP) materials can be traced from its theoretical origins, through the identification of useful compositions, to full commercialization. The future industrial challenge will be to define and develop applications which take advantage of the unique properties of these materials. 

Liquid crystal polymer materials offer many advantages over conventional thermoplastics in injection moulding, including low mould shrinkage, minimum warpage and distortion, fast cycle time, ability to mould thin parts, low moisture absorption, and excellent chemical resistance. The mechanical properties are comparable to those of materials filled with short glass fibres. 

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