Polyanhydrides .9. Thermotropic poly(ester-anhydride)s derived from naphthalene-2,6-dicarboxylic acid and biphenyl-4,4'-dicarboxylic acid

Two series of thermotropic poly(ester-anhydride)s, LC-PEAs, were studied. The first series was prepared by polycondensation of naphthalene-2,6-dicarbonyl dichloride with silylated 4-hydroxybenzoic acid, silylated and substituted 4-hydroxybenzoic acids or silylated 6-hydroxy-2-naphthoic acid. A second analogous series of LC-PEAs was prepared by means of biphenyl-4,4'-dicarbonyl dichloride. Most LC-PEAs were semicrystalline materials with melting temperatures (T-m) in the range of 280-400 degrees C. All LC-PEAs formed a nematic melt above T-m, but due to the high temperatures the isotropization was affected by thermal degradation.