Carbon nanotubes/silver nanoparticles/poly(azo-thiourea) hybrids: Morphological, tensile and conductivity profile

Abstract

Carbon nanotubes were decorated with silver nanoparticles (CNTs/Ag) using N,N-dimethylformamide as a reductant in this study. A new heteroaromatic azo-polymer, poly(azo-thiourea) (PAT) was also prepared using 4-(4-aminobenzyl)benzenamine and diazonium salt solution of 2,6-diaminopyridine. PAT was subjugated as a matrix material to synthesize new hybrids using CNTs/Ag as filler. To prepare the nanocomposites, melt compounding and solution mixing techniques were employed. The results showed that the CNTs/Ag effectively improved the electrical conductivity, mechanical and thermal properties of CNTs/Ag/PAT nanocomposites. The solution mixing method resulted in a better dispersion of filler leading to higher mechanical strength (52.47–54.36 MPa) relative to melt system (29.11–39.22 MPa). The solution method also gave better electrical properties due to lack of oxidization of silver nanoparticles. Consequently, increasing the filler content from 1 to 5 wt% increased the electrical conductivity from 4.89 to 6.12 S/cm. Scanning electron micrographs revealed fine dispersion of filler and adhesion of matrix to the nanotube surface in solution method. Thermal stability of the materials studied via 10% gravimetric loss was found to increase from 522℃ to 543℃ (solution) and 512℃ to 521℃ (melt). Similarly, glass transition of solution mixed system (242–249℃) was higher than the melted one (212–217℃).