Prediction of the effective thermal conductivity of carbon nanotube‐reinforced polymer systems

A study dealing with the effect of the carbon nanotubes (CNTs), at various weight fractions, on the effective thermal conductivity of a CNT‐reinforced polymer by associating it with the Kapitza resistance ( R _Kap ) phenomena is presented. The finite element method was utilized as a tool for the models' solution by using the principles of the representative volume element. An intermediate continuum layer between polymer matrix and CNTs was considered for the representation of the R _Kap phenomena. The influence of the intensity of R _Kap phenomena at various CNT contents was investigated through the parametric study of the R _Kap value and the thickness of the intermediate layer. The predicted results were compared against experimental measurements derived from an equivalent CNT–epoxy resin system. The discrepancy between calculated and measured values is diminished when the R _Kap phenomena are taken into account, thus confirming the existence of thermal resistance between the CNTs and the polymer matrix. The R _Kap rise as the % CNT weight content is increased. This behavior is correlated to the higher CNT agglomeration at higher CNT contents, which is proven by the scanning electron microscopy and thus providing a first indication of the effect of the CNT agglomeration on the effective thermal conductivity at various CNT contents. POLYM. COMPOS., 35:1997–2009, 2014. © 2014 Society of Plastics Engineers