Liquid‐crystalline main‐chain polymers with a poly(p‐phenylene terephthalate) backbone, 8. Synthesis and characterization of polyesters with 3‐ethoxypropoxy and 6‐(pentyloxy)hexyloxy side chains

Abstract

The influence of replacing a methylene group in the middle of the side chain of alkoxysubstituted poly@-phenylene terephtha1ate)s by an oxygen atom was investigated by differential scanning calorimetry (DSC), rheological measurements and X-ray diffraction. Due to the presence of the oxygen atom the side chains of the polymer with long side chains (PTAlZ(0)HQ) lose their ability to crystallize. Except for this difference and a shift of the transition temperatures to lower temperatures, this polymer shows a similar phase behaviour compared to the corresponding alkoxy-substituted polyester PTA12HQ. The polymer with short side chains, FTA6(0)HQ, shows a similar behaviour as the corresponding polymer without an extra oxygen atom, PTA6HQ. Only the transition to the nematic mesophase is shifted to lower temperatures.