Structure and Mechanical Properties of Rigid Rod Polymers Having Flexible Side Chains

Abstract

A series of rigid rod polyesters with flexible n-alkoxy side chains of different lengths has been studied in order to determine the structure and properties of the polymers in various states (solid state, mesophase, melt). It has been shown that various supermolecular structures can be obtained depending on the length of the side chains and on the preparation conditions of the samples. The relaxation behavior of the polymers has been investigated by dynamic mechanical measurements. Complex relaxation spectra have been observed and the assignments of molecular motions and structural rearrangements to the observed mechanical relaxation transitions have been made. The rheological behavior studied in the mesophase and in the melt has indicated that in some polymers typical liquid crystalline properties can be observed as for example the flow thinning effect. Large deformations of polymer films as well as the structure and mechanical strength of oriented ssmples, have also been studied.