Multifunctional carbon fiber/epoxy laminates for thermal energy storage and release

This work aims at developing multifunctional composite laminates with thermal energy storage (TES) capabilities. Structural laminates were fabricated with an epoxy resin, a carbon fiber fabric, and a shape-stabilized phase change material (PCM) based on paraffin and carbon nanotubes (CNTs). The PCM kept its ability to melt/crystallize in the laminates, and the total melting enthalpy was proportional to the paraffin content, as well as the thermal conductivity of the laminates through thickness direction. The capability of the TES laminates to contribute to the thermal management was also proven by monitoring their cooling rates through a thermal camera. The flexural modulus was only slightly affected by the PCM, while a decrease of flexural strength and strain at break was detected. Microscopy investigations highlighted that this could be attributed to the preferential distribution of the PCM in the interlaminar region and to the poor adhesion between the PCM particles and the epoxy matrix. Therefore, current activities are aimed at encapsulating the paraffin in a sol-gel derived organosilica shell obtained by hydrolysis-condensation of methyltriethoxysilane in oil-in-water emulsion. Preliminary efforts resulted in the production of submicron spherical capsules with a maximum total enthalpy of 143 J/g.