Anisotropic wholly aromatic polyester derived from 4-hydroxy-4'-carboxy azobenzene and process for preparation

A wholly aromatic polyester capable of forming an anisotropic melt at a temperature below approximately 350.degree. C. consisting essentially of the recurring moieties I and II, which may include substitution of at least one hydrogen atom present upon an aromatic ring wherein:

• I is ##STR16## and II is selected from the group consisting of ##STR17## and mixtures thereof, with said optional substitution if present being selected from the group consisting of an alkyl radical of 1 to 4 carbon atoms, an alkoxy radical of 1 to 4 carbon atoms, halogen, and mixtures thereof, and wherein said polyester comprises approximately 20 to 80 mole percent of moiety I and approximately 20 to 80 mole percent of moiety II.

A wholly aromatic polyester capable of forming an anisotropic melt at a temperature below approximately 350.degree. C. consisting essentially of the recurring moieties I, II, and III, which may include substitution of at least one hydrogen atom present upon an aromatic ring wherein:

• I is ##STR20## II is at least one symmetrical dioxy aryl moiety of the formula --O-Ar-O-- wherein Ar is a divalent radical comprising at least one aromatic ring, and
• III is at least one symmetrical dicarboxy aryl moiety of the formula ##STR21## wherein Ar is a divalent radical comprising at least one aromatic ring, with said optional substitution if present being selected from the group consisting of an alkyl radical of 1 to 4 carbon atoms, an alkoxy radical of 1 to 4 carbon atoms, halogen, and mixtures thereof, and wherein said polyester comprises approximately 30 to 70 mole percent of moiety I, approximately 15 to 35 mole percent of moiety II, and approximately 15 to 35 mole percent of moiety III.