Chemical Oxidative Condensation of Benzidine in Non-Aqueous Medium: Synthesis and Investigation of Oligomers and Polymer with Benzidine Diimine Units

The oxidative condensation of benzidine has been carried out in acetic acid media using potassium peroxydisulfate as the oxidizing agent. Using different monomer-oxidant molar ratios, benzidine dimer, trimer, and polymer have been synthesized for the first time. It was established that the polybenzidine structure is composed from a sequence of benzidinediimine and diphenylene units with amino/amino end groups and thus proves the possibility of ammonia elimination during the oxidative polymerization of aromatic diamines. The method seems to be common for the synthesis of polymers with the sequence of aromatic diimine and arylene units. TGA analysis of the obtained trimer and polymer was investigated, and the high thermostability of both the polymer and trimer was revealed. According to the obtained data, both polymer and trimer matrix decomposition started at 300 degrees C, and at 600 degrees C, 75.94% and of 69.40% of the initial weight remained, correspondingly. Conductivities of the polymer and trimer show a semiconductor-type change from temperature and after doping show an increase in conductivity up to 10(-4) Sm/cm.

Automated summary

The oxidative condensation of benzidine using potassium peroxydisulfate in acetic acid medium resulted in the synthesis of benzidine dimer, trimer, and polymer for the first time, with a polybenzidine structure composed of benzidinediimine and diphenylene units. Thermal analysis showed high thermostability, with decomposition starting at 300 degrees C and significant weight retention at 600 degrees C. The conductivities of the polymer and trimer exhibited semiconductor behavior, increasing up to 10(-4) Sm/cm after doping.