Thermotropic liquid crystal aromatic copolyesters

THERMOTROPIC LIQUID CRYSTAL AROMATIC COPOLYESTERS CONTAINING CYCLOALIPHATIC... 

They are thermotropic liquid crystals obtained from aromatic homo- or copolyesters, which exhibit particularly high thermomechanical characteristics while preserving excellent impact strength up to very low temperatures. Taking into account their high cost, they are utilized only for high-valued applications, particularly in electronics industry. 

A great many aromatic polyesters and copolyesters which show thermotropic behaviour have now been reported, particularly in the patent literature. The copolyesters may contain either combinations of different types of mesogenic units or combinations of mesogenic and non-mesogenic (non-linear) units. The structures of many of the different types of monomers used to form liquid crystal aromatic polyesters and copolyesters are shown in Table 3. ... 

Thermotropic aromatic copolyesters (liquid crystal polymers) (LCP) Vectra Xydar Zenite Ticona Solvay Dupont High temperature fabricated parts, E/E interconnects, connectors, medical equipment, aerospace, automotive and industrial parts... 

In yet another classification, they can be broadly classified into three classes namely Aromatic polyamides or Aramides like Kevler, Twaron, etc., Aromatic heterocyclic and Aromatic copolyesters (Pegoretti and Traina 2009). Aromatic heterocyclic LCPs are kind of lyotropic liquid crystal containing wholly aromatic molecular framework with fused heterocyclic ring along the main chain. Aromatic copolyesters exhibit thermotropic behavior and are characterized by high... 

If we incorporate aromatic sfructures into the polymer backbone, not only can we make the molecule rigid and rodlike, we can also raise its Tg, make it thermally stable at high temperatures, and impart high strength and stiffness. Thus, linear aromatic thermoplastics such as semicrystalline polyetherether ketone have a Tg of 143°C and a maximum continuous-use temperature of 250°C [49]. Ultrastiff, rodlike molecules can also be made to form liquid crystals from both the melt and solution [50] molecules such as poly-/ -phenyleneter-ephthalamide and thermotropic copolyesters can be spun into fibers in a highly oriented, extended-chain form to yield strength and stiffness values up to 3 GPa and 140 GPa, respectively. 

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