Thermal Characterization of Polyester Resin Composites Loaded with Graphite Rod-like Inclusions Using Front-Face Laser-Flash Thermography

One of the most challenging aspects in the manufacture of composite materials is understanding how the geometry and distribution of the inclusions influence their thermal and mechanical properties. In this study, we report the longitudinal thermal properties of vertically aligned graphite rods embedded in a polymer matrix with various geometric arrangements: circular, polygonal, and rectangular. The thermal diffusivity was measured using the front-face laser-flash thermography technique, which provided images of the heating-cooling process from the sample surface. As a first insight, we analyze thermal transport by following the evolution of the thermograms of all the samples’ surfaces and applying a conventional approach. Additionally, we analyze the thermograms in specific regions based on the rods’ distribution geometry to determine the effective thermal properties in each area, which can be directly linked to the graphite rod content. This approach demonstrates how the distribution of the rods significantly influences the heat transport properties. To deepen our understanding, we propose a modified Nan’s model by considering a variation in the geometrical shape factor. Our findings contribute to the development of composites with adjustable thermal properties and offer practical insights for designing systems for thermal management, highlighting the direct applicability of this research.