Liquid-crystalline aromatic polyesters with phenylalkyl side chains

Thermotropic liquid‐crystalline poly(1,4‐phenylene terephthalate)s with phenylalkyl side chains were synthesized. The influence of this novel type of substituent on the thermal properties and solubility behavior is discussed. In common solvents soluble, liquid‐crystalline polyesters with low transition temperatures were obtained when the phenylalkyl substituent was introduced in combination with a bulky substituent or when both phenyl rings were substituted with phenylalkyl side chains. When poly(1,4‐phenylene terephthalate) is only monosubstituted with a phenylalkyl substituent in the 1,4‐phenylene unit, the polyesters have melting temperatures above 310°C and are only soluble in solvents such as p‐chlorophenol.