Theoretical Analysis of Thermal Conductivity of Polymer Systems Filled with Carbon Nanotubes

Authors Е.А. Lysenkov, R.V. Dinzhos

V.O. Sukhomlynskyi Mykolaiv National University, 24, Nikolska St., 54030 Mykolayiv, Ukraine

Issue Volume 11, Year 2019, Number 4
Dates Received 21 April 2019; revised manuscript received 02 August 2019; published online 22 August 2019
Citation Е.А. Lysenkov, R.V. Dinzhos, J. Nano- Electron. Phys. 11 No 4, 04004 (2019)
PACS Number(s) 73.63.Fg, 74.50.+ r
Keywords Thermal conductivity (2) , Polymer nanocomposites, Models of thermal conductivity, Carbon nanotubes (14) , Percolation.

The theoretical models of thermal conductivity of polymer nanocomposites, such as Russell’s, Lewis-Nielsen, Nan’s, Lichtenecker’s, percolation models, and their accordance to experimental results for the polymer-carbon nanotubes (CNT) systems are analyzed. The experimental results of the concentration dependence of the thermal conductivity for polyethyleneoxide-CNT (crystalline matrix) and crosslinked polyurethane-CNT (amorphous matrix) systems were used to establish the correspondence between the theoretical models and the experiment. It is set that Russell’s model partially describes the experimental data, when the filler’s content is low. However, this model cannot describe the change in thermal conductivity with an increase in the filler content for systems filled with СNT. The Lewis-Nielsen model assumes a linear relationship between the thermal conductivity and the filler content. However, such behavior of the theoretical curve does not correspond to the jump-like dependence of the thermal conductivity obtained from the experiment. It is established that using the Nan’s model, it is impossible to accurately describe the experimental results of the thermal conductivity of the selected systems. Using the modified Lichtenecker’s model, it is possible to obtain a partial agreement of the theoretical curve with the experimental results. This model allowed to determine the value of thermal resistance of the investigated polymer-CNT systems, which is equal to 2·107 W/(m2·K). It is discovered that the percolation model demonstrates good correspondence with the experimental data of the thermal conductivity for the polymer-CNT systems. This model accounts the presence of the percolation threshold. The advantage of this model is the accounting of the structural features of the percolation cluster formation, which are expressed through the universal critical indexes k and q. However, the critical indexes for the investigated polymer-CNT defined using the percolation model systems were found to be lower than the theoretical ones that is associated with a high degree of aggregation of CNT.

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