Research of the thermal storage properties of thermally conductive carbon fiber-reinforced paraffin/olefin block copolymer composite phase change materials with thermotropic flexibility

This study focuses on the fabrication and evaluation of paraffin (PA)/olefin block copolymer (OBC)/carbon fiber (CF) composite phase change materials (CPCMs) prepared using the melt impregnation process. The resultant PA/OBC/CF CPCMs exhibit superior thermal stability below 200 degrees C and maintain excellent shape stability at 60 degrees C. These characteristics are attributed to the alternating soft and hard segments of OBC, wherein the hard segments prevent liquid leakage from PA. The distinct structure of OBC further lends flexibility and recyclability to the PA/OBC/CF CPCMs. The latent heat of these CPCMs ranges from 169.1 to 197.6 J/g. Notably, the CPCMs variant (PA/OBC/CF-1) with 2 wt% CF addition retains 95 % of its initial latent heat even after 100 thermal cycles, thereby demonstrating superior cycling stability. The thermal conductivity of CPCMs with 10 wt% CF is 1.3 times that of pure PA. This significant improvement in thermal conductivity is attributed to the heat conduction pathways provided by the fibrous CF. These results indicate that the fabricated CPCMs offer substantial promise for utilization in low-temperature waste heat recovery applications.