Aromatic Main Chain Liquid Crystalline Polymers

1 Aromatic Main Chain Liquid Crystalline Polymers 

It is far beyond the scope of this chapter to present a comprehensive overview on the different structures of aromatic main chain LCPs and take into account the various property and application aspects. The objective of this chapter is to discuss the impact of structural concepts in modifying the properties of aromatic LCPs, focusing here on aromatic thermotropic LC polyesters. This will be discussed for selected examples. Conclusions from the work on polyesters are transferrable to other classes of thermotropic and lyotropic aromatic polymers. 

2 Structural Modification Concepts of Liquid Crystal Polymers (LCPs) 

Under thermodynamic considerations, high melting temperatures are the result of high melting enthalpies and low melting entropies. Consequently, the structural modification concepts are based either on a de- 

The incorporation of monomer units of different length, such as p-phenyl, p-bi-phenyl, or p-terphenyl moities (Fig. 2a), causes the linkage groups to be positioned at random distances along the polymer chain. As a consequence, the intermolecu-lar interactions, particularly of the polar linkage groups, are partially excluded. The overall chain stiffness increases with the amount of the longer aromatic unit. 

---

The thermotropic aromatic main chain liquid crystalline polymers are also prepared by the phase transfer catalyzed aromatic nucleophilic polymerization [87]. Polyetherification of bis(4-chloro-3-nitrophenyl) sulfone with mesogenic aromatic diols is shown below ... 

Greiner A, Schmidt HW (1998) Aromatic Main Chain Liquid Crystalline Polymers. In Demus D, Goodby J, Grey GW, Spiess H-W, Vill V (eds). Handbook of Liquid Crystals,... 

Aromatic Main Chain Liquid Crystalline Polymers. 3... 

---