Nanoblends of novel polyesters with polyaniline: Conductivity and heat-stability studies

Abstract

The present work initially deals with the fabrication of a new generation of polyesters (bearing thiophene, azomethine, thiourea and ether moieties) and subsequent blending with polyaniline (PAN) exhibiting extremely valuable nanoblend characteristics. Few poly(azomethine-thiourea-ester)s (PATEs), by the polycondensation of a new diol 4,4 0 -oxydiphenyl bis((E)-1-(4-hydroxobenzylidene)thiourea) with thiophene-2,5-dicarbonyl/terephtaloyl chloride, were synthesized. The polymers obtained were characterized by Fourier-transform infrared, proton-nuclear magnetic resonance, solubility, solution viscosity, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry and wide-angle x-ray diffraction. The polymers exhibited high molar mass (77-89 Â 10 3 ) and thermal stability (T 10 528-531 C, glass transition temperature (T g ) 265-268 C). Then the electrically conducting blends, of PAN dispersed in the PATEs matrix, were prepared by mash-blending and melt-blending techniques. Materials obtained by conventional melt-blending approach generated an efficient conductive network compared with those produced by mash blending. Field emission scanning electron microscopy images displayed nanoblend morphology of the melt-blended system, owing to increased physical interactions (hydrogen bonding and p-p stacking) between the two polymers. Moreover, miscible blends of thiophene-based PATE/PAN led to superior conductivity (1.5-2.1 S/cm) and heat stability (T 10 503 C) even at low PAN concentration relative to previous thiophene, azomethine or PAN-based structures.