Design and Synthesis of New Thermally Stable Polyesters containing Azo and Phenylthiourea Groups

Abstract

A series of new soluble, thermally stable polymers that contain phenylthiourea and azo groups in the polymer backbone were synthesized from a novel bisphenol and diacid chlorides. The novel bisphenol containing phenylthiourea and azo groups was synthesizedinthreesteps. In the first step, 4,4‘-bis(thiourea) biphenyl (BTB) was from 4,4‘-diaminobiphenyl and ammonium thiocynate. The second step involved the diazodization reaction of 4-aminophenol to give the diazonium chloride salt. The third step in the preparation of the monomer was the coupling of bisthiourea (BTB) with the diazonium chloride in the presence of an alkali which resulted in 4,4‘-bis( p-hydroxyphenyl azo thiourea)biphenyl (HP-ATB). The final step was the synthesis of polyesters by polycondensation reaction of this monomer with various acid chlorides (both aromatic and aliphatic). The materials were characterized by solution viscosity, UV-Vis, Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry and thermogravimetric analysis. Solubility of the polymers was also tested with different solvents, which can be an important parameter for the processability of the polymer. The synthesis and characterization of the novel monomer and polymers is discussed herein.