Synthesis and properties of new polyamide/multiwalled carbon nanotube nanocomposites containing a pyridine group

The effects of multiwalled carbon nanotubes ( MWCNTs ) on the thermal properties and flame retardancy of a new polyamide ( PA ) derived from glutaric acid and aromatic diamine were investigated in this work. The synthesized PA containing pyridine and trialkylamine groups was characterized by 1 H NMR and SEC . The PA unit structure was geometrically optimized at the B 3 LYP /6‐311 ++ G(d, p) level of theory. PA showed a glass transition temperature of 151 ºC . PA nanocomposites containing two different amounts of MWCNTs were prepared via the solution intercalation technique with the solvent N , N ‐dimethylacetamide. Transmission electron microscopy showed that MWCNTs were exfoliated in the polymer matrix, resulting in well‐dispersed morphologies at 3 wt% MWCNT content. The redox behaviors of PA and the nanocomposites were examined using cyclic voltammetry ( CV ). PA showed a reversible oxidation process in the CV scan. Thermal and flammability properties of the nanocomposites were studied by TGA in nitrogen and air, DSC and with a microscale combustion calorimeter. The TGA results showed that the addition of MWCNTs resulted in a substantial increase in the thermal stability and char yields of the nanocomposites compared with neat PA . The heat release rate and total heat release were significantly reduced in the presence of MWCNTs .