Sanidic polyesters

Chiral sanidic polyesters derived from copolymerizations of (S,S)-2,5-bis(2-meth-ylbutyloxy)terephthalic acid, 2,5-bis(dode-cyl)terephthalic acids, and 4,4 -dihydroxy-biphenyl have been reported [22]. These... 

Recent developments in the substitution of completely aromatic LC polyesters have produced polymers which show improved solubilities and reduced transition temperatures (29). The presence of these side groups provides a method for producing polymers that are compatible with other similarly modified polymers. In this way, blends of rigid and flexible polymers can be prepared. Substituents have included alkyl, alkoxy (30) and phenyl alkyl groups (21), some of which lead to mesophases that have been reported as being "sanidic" or board-like. This approach has been used with both polyesters and polyamides and has lead to lyotropic and thermotropic polymers depending on the particular composition used. Some compositions even show die ability to form both lyotropic and thermotropic mesophases (22). 

Tetrasubstituted polyesters with long alkyl side chains on the hydroquinone moiety connected via ether or ester linkages have been reported [20 c] (Fig. 12). In these polyesters, the tetrasubstituted moiety can be considered as a discotic mesogen. The polyesters with Z = H are highly soluble and have low melting temperatures (T n < 100 °C) and low clearing temperatures in the range of 123-260°C. The type of mesophase formed is referred to as sanid-... 

The data correlate with a sanidic layer structure as sketched in Figure 5. Similar orientation in the bulk phase has been observed for other so-called hairy-rod molecules with solubilizing side groups like polyesters and polyphenylenes [22 - 24]. 

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