Multiscale finite element modeling of effective thermal conductivities of short glass fiber/polyethylene composites containing copper nanoparticles

Abstract

The main purpose of this work is to establish a multiscale finite element modeling approach to evaluate thermal conductivities of polymer composites reinforced by both nanoparticles and microfibers. The hybrid material includes a polyethylene matrix, copper nanoparticles, nanoparticle/polymer interphase, and short glass microfibers. Initially, a nanoscale representative volume element in which nanoparticles are randomly distributed within polyethylene is generated. Then, a microscale representative volume element is constructed in which aligned glass fibers are embedded in the nanoparticle-filled polymer as the host material. The proposed modeling approach is validated against existing literature. Influences of the interphase region and variation in its thickness and thermal conductivity, spherical and cylindrical shape of nanoparticles, aspect ratio and volume fraction of both nano- and micro-scale reinforcements as well as the nanoparticle agglomeration on the longitudinal and transverse thermal conductivities of polymer composites are examined. It is found that the inclusion of copper nanoparticles into the polymer matrix results in an enhancement of thermal conductivities of glass fiber/polyethylene composites. Increasing the nanoparticle aspect ratio improves the hybrid composite thermal properties, whereas agglomeration of nanoparticles reduces thermal performance due to localized inhomogeneity and disrupted conduction pathways. In addition, interphase characteristics are identified as critical factors governing the heat transfer efficiency of nanoparticle/glass fiber/polyethylene composites. The findings provide valuable insights for designing lightweight, thermally efficient materials applicable in electronic packaging, heat exchangers, and thermal interface systems. © 2025 Elsevier Ltd