Theoretical models, nanotube composites

In order to estimate the theoretical upper bounds for the electrical conductivities of polymer nanotube composites, equation (15.1) was used to calculate conductivity values for model composites based on both SWNT and MWNT. The values are included in Table 15.2 together with the electrical conductivities of individual CNTs as reported in the literature. Although arc-synthesized MWNTs are likely to possess higher conductivities than CVD-grown ones, no distinction is made in the present analysis between the two types due to the unavailability of reliable data. An electrical conductivity of IE-9 S/m is taken to represent the conductivity of a typical polymer matrix. 

It can be seen that, with regard to the pure matrix, the elastic modulus, tensile strength and strain at break increase with nanotube loading. On the other hand, the addition of 10 MWNTs impart to the matrix a higher level of reinforcement than 10 phr of carbon black. Many factors could potentially explain the superior reinforcing efficiency of carbon nanotubes and among them, the filler aspect ratio is expected to play an important role in the mechanical response of the composite. Experimental data can be usefully compared to theoretical model predictions, especially those of Guth [71] and Halpin-Tsai [72]. 

Mechanical properties - Numerous theoretical works have been done to predict the mechanical properties of reinforced composites. Some of these models are more sophisticated, but in order to understand why nanotubes are ideal reinforcement particles, the rule of... 

Tserpes, K. I., Panikos, R, Labeas, G., and Panterlakis, S. G. Multi-scale modeling of tensile behavior of carbon nanotube-reinforced composites. Theoret and Appl Fract Mech., 49,51-60(2008). 

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