Thiophene- and silarylene-containing polyesters. Resonance effect on conductivity after polarization in an external electric field

Abstract

Polyesters were synthesized by direct polycondensation of thiophene-2,5-dicarboxylic acid and five different silarylene-containing diphenols using a tosyl chloride/pyridine/N,N-dimethylformamide system as a condensing agent. Polymers were obtained in good yields and were characterized using Fourier transform infrared and NMR ( 1H, 13C, 135-DEPT and 29Si) spectroscopy and elemental analysis. All polymers were completely soluble in aprotic organic polar solvents such as dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone. The range of effective mass of the polymers (m/z) was 1 × 10 5-2 × 10 5, determined using electrospray ionization mass spectrometry. Asymmetry and steric hindrance prevented dense packing of the polymeric chains, showing glass transition temperatures between - 78 and - 51 °C and loss of thermal stability at 177-199 °C (10% weight loss). Additionally, the melting points of the polyesters were found to be in the range 62-67 °C. Because of this, the samples wer