On Refining the Relationship between Aspect Ratio and Percolation Threshold of Practical Carbon Nanotubes/Polymer Nanocomposites

Four different aspect ratio (AR) based multiwall carbon nanotube (MWNT)/thermoplastic elastomer (TPE) polymer nanocomposites were fabricated by melt blending. In contrast to proposed mathematical models, electrical percolation thresholds of resulting nanocomposites displayed an oscillating, non-monotonic relation with increase in AR. Experimental results suggested that mathematically calculated nominal AR of MWNT was an unclear parameter to predict the percolation threshold of polymer nanocomposites. Instead, a more clear approach taking into consideration the diameter and length of nanotubes individually rather as a combined parameter of AR explained fairly well the relation between MWNT dimensions and percolation threshold.