Effect of methylene spacer length on the molecular mobility and dipole moment of poly(azomethine esters) with azomethinearomatic groups in the ortho position

Abstract

Relaxation of dipole polarization is studied and dipole moments are measured for poly(azomethine esters) with rigid azomethinearomatic fragments in the ortho position and methylene spacers of various lengths in the backbone chain. These polyesters in solution are shown to be characterized by four relaxation processes. The molecular mobility parameters (relaxation time and activation energies of three local processes) depend nonmonotonically on the length of the methylene spacer and on the evenness or oddness of the number of methylene units in the spacer in particular. For the fourth large-scale process, these activation parameters have high values and monotonically increase with the spacer length. The dipole moment of the polyester is shown to be higher when the number of methylene units in the spacer is odd. This may be due to specific conformational features of the ester part of the macromolecule.