Thermal and morphological study of paraffin/SEBS/expanded graphite composite phase change material for thermal energy storage

This work aims to develop a high thermal conducting and leakage-proof composite phase change material (CPCM) for thermal energy storage (TES) applications. A leakage-proof shape-stable phase change material (SPCM) has been prepared by impregnating paraffin into the network of polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene (SEBS) tri-block copolymer. In order to improve the thermal conductivity of paraffin/SEBS composite, expanded graphite (EG) has been directly incorporated into paraffin/SEBS (4:1) composite. Two different mass fractions of EG, i.e., 1 wt% and 5 wt%, have been chosen for the thermophysical study of leakage-proof SPCM named CPCM1 and CPCM2, respectively. Structural, morphological, and thermal studies of prepared composites have been carried out by XRD, FTIR, SEM, TGA, and DSC. The latent heats of prepared SPCM, CPCM1, and CPCM2 composites have been found as 167.91 J/g, 163.25 J/g, and 146.71 J/g, respectively. The thermal conductivities of composites have been measured by Laser Flash Apparatus (LFA). Results show that the thermal conductivity (TC) of CPCM1 and CPCM2 remarkably increases to 0.501 Wm−1K−1 and 1.301 Wm−1K−1, respectively, which is 2.8 and 7.35 times of paraffin/SEBS composite (0.177 Wm−1K−1). Therefore, findings suggest that the CPCM1 and CPCM2 samples have a great potential for TES application, specifically for solar water heating systems.