The effect of carboxylic acid group on conductivity of the aromatic polyazomethines and char composites

One of the properties gained by COOH groups of polymer, exists in aromatic polyazomethine (PAM) in the main chain, is the increase in the conductivity. In this study, the PAMs including carboxylic acid in subgroups as condensation polymerization products were obtained. The electrical conductivity of the polymers was enhanced by many orders of magnitude by PAM. The carboxylic acid group increase the electrical conductivity in two ways are: (i) increasing chain flexibility and (ii) allowing movement of the charge carrier more easily along the chain. Additionally, in this study, the polymer composites were obtained using the carbon material (char) derived from the 400°C pyrolysis of waste polyethylene terephthalates. It was observed that conductivity also increased due to char in the composites formed by the PAMs with char. The lowest Eg value of 0.55 eV was determined in poly-2-carboxyl-1,4-bis[(diphenylether)methylene]phenylenediamine/char composite. The structures of the obtained polymers were confirmed by FTIR, UV–vis, TGA,1H NMR, and EDX techniques. The molecular weight distribution parameters of the synthesized compounds were determined with the size exclusion chromatography. POLYM. COMPOS., 35:372–380, 2014. © 2013 Society of Plastics Engineers