Emissivity Study of Hierarchical GFRP-CNT Composites

Hierarchical composites are materials comprised of multi-scale microstructures ranging from nano to micron size. Glass fibre-reinforced plastic (GFRP) laminated composites with multi-walled carbon nanotubes (CNTs) are one such example. Recent literature studies have shown a significant effect of aligning CNTs with respect to the loading axis on the structural life of a GFRP test specimen subjected to static and dynamic loads. Efforts are underway in the scientific community to measure damage accumulation in such hierarchical structural materials using the infrared (IR) thermography technique. In the present work, a GFRP laminate with 0.1% CNTs was fabricated using a combination of wet hand layup and vacuum bagging techniques. The following set of specimens was fabricated: (i) GFRP without CNTs (C0), (ii) GFRP with randomly dispersed CNTs (CR), (iii) GFRP with aligned CNTs (CꞱ), (iv) neat epoxy (C0-G), and (v) epoxy with randomly dispersed CNTs (CC-G), with the aim of determining the effect of composition on the emissivity of such hierarchical materials. C0 material had the lowest emissivity (0.94) while the CꞱ had the highest (0.99). This study would set the reference for further work on the use of IR techniques to indirectly measure damage accumulation in GFRP hierarchical composites.