A micromechanics-based model for temperature-dependent heat conduction of silver nanowire/aligned short fiber-reinforced polymer nanocomposites

Thermal management in composite materials used in high-tech industries is a growing criticality. In this contribution, the effect of adding silver nanowires (AgNWs) on the temperature-dependent heat conduction coefficients of aligned short carbon fiber-reinforced polymer nanocomposites is investigated using a multiphase micromechanical model. First, the thermal conductivity of AgNW-filled polymer materials is evaluated within the framework of the micromechanics. The most important microstructural features including percentage, length, diameter, and anisotropic behavior of AgNWs, as well as the nanofiller/polymer interfacial thermal resistance (ITR) are incorporated. Then, a unit cell-based model in conjunction with a 3D representative volume element is developed to predict the transverse and longitudinal thermal conductivities of AgNW/aligned short fiber-reinforced nanocomposites. Results show that thermal properties of short fiber composites are improved significantly by the addition of AgNWs. Also, using AgNWs with a smaller diameter and a greater length is an efficient means to achieve much better thermal conductivity enhancement. A lower ITR between AgNWs and polymer matrix can enhance the heat conduction coefficients. It is noticed that the longitudinal thermal conductivity of the AgNW/aligned short fiber-reinforced nanocomposite increases with increasing fiber aspect ratio, while its transverse thermal conductivity is not affected by varying the aspect ratio. Comparisons show that the micromechanical predictions agree well with the experimental measurements. Our findings can be useful for the design and optimization of hybrid nanocomposites containing AgNWs with tailored thermal transport properties for advanced industries.