Nanotube-polymer ratio

The gap between the predictions and experimental results arises from imperfect dispersion of carbon nanotubes and poor load transfer from the matrix to the nanotubes. Even modest nanotube agglomeration impacts the diameter and length distributions of the nanofillers and overall is likely to decrease the aspect ratio. In addition, nanotube agglomeration reduces the modulus of the nanofillers relative to that of isolated nanotubes because there are only weak dispersive forces between the nanotubes. Schadler et al. (71) and Ajayan et al. (72) concluded from Raman spectra that slippage occurs between the shells of MWNTs and within SWNT ropes and may limit stress transfer in nanotube/polymer composites. Thus, good dispersion of CNTs and strong interfacial interactions between CNTs and PU chains contribute to the dramatic improvement of the mechanical properties of the... 

Bauhofer W, kovacs JZ (2009) A review and analysis of electrical percolation in carbon nanotube polymer composites. Compos Sci Technol 69 1486 Behnam A, Guo J, Ural A (2007) Effects of nanotube alignment and measurement direction on percolation resistivity in single-walled carbon nanotube films. J Appl Phys 102 044313 Berhan L, Sastry SM (2007) Modeling percolation in high-aspect-ratio fiber systems. L Soft-core versus hard-core models. Phys Rev E 75 041120 Berman D, Orr BG, Jaeger HM, Goldman AM (1986) Conductances of filled two-dimensional networks. Phys Rev B 33 4301... 

Chen L., Ozisik R., and Schadler L. S., The influence of carbon nanotube aspect ratio on the foam morphology of MWNT/PMMA nanocomposite foams. Polymer 2010, 51, 2368-2375. 

Silva, (., Ribeiro, S Lanceros-Mendez, S., and Simoes, R. (2011) The influence of matrix mediated hopping conductivity, filler concentration, aspect ratio and orientation on the electrical response of carbon nanotube/polymer nanocomposite. Composite Science and Technology, 643,... 

Electrical conductivity in nanotube-polymer composites exhibits percolation-type behavior, where the presence of interconnected nanotube network results in a dramatic increase of the electrical conductivity. Physical parameters of composite materials such as electrical conductivity, percolation threshold v ), and critical exponent (t) have been intensively studied to achieve polymer-CNT conductive composites at low filler concentrations. However, as already mentioned, numerous studies show that the percolation threshold and conductivity depend strongly on the polymer type and synthesis method, aspect ratio of CNTs, disentanglement of CNT agglomerates, uniform spatial distribution of individual CNTs, and degree of alignment. 

The future remains bright for the use of carbon materials in batteries. In the past several years, several new carbon materials have appeared mesophase pitch fibers, expanded graphite and carbon nanotubes. New electrolyte additives for Li-Ion permit the use of low cost PC based electrolytes with natural graphite anodes. Carbon nanotubes are attractive new materials and it appears that they will be available in quantity in the near future. They have a high ratio of the base plane to edge plain found in HOPG. The ultracapacitor application to deposit an electronically conductive polymer on the surface of a carbon nanotube may be the wave of the future. 

Thanks to their high aspect ratio, CNTs percolate to form a network at very low loading in the polymer matrix and lead to substantial enhancement of several functional properties, such as flame retardancy. Two different types of CNTs, single-walled nanotubes (SWNT) with... 

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