Synthesis, chemical and chemical-physical characterisation of new thermotro
pic copolymers containing ester and hydrazidic units are reported. The poly
mers consist of polyester blocks linked together through p-phenylenhydrazid
ic units. By varying the nature and the relative percentage of the comonome
rs in the polyester block, it is possible to obtain thermotropic copolymers
with melting temperatures well below the degradation, with a good range of
stability of the mesophase, and with heat resistance properties similar to
those of homopolymeric polyhydrazides.