Improved thermal properties of stearic acid/high density polyethylene/carbon fiber composite heat storage materials

Abstract Composite phase change materials (CPCM) with improved thermal properties were fabricated by encapsulating stearic acid (SA) into high-density polyethylene (HDPE) with carbon fiber (CF). The HDPE acted as the supporting materials to prevent SA leakage. CF was introduced to enhance the thermal conductivity of the CPCM. Some characterization measurements were carried out to investigate the CPCM thermal properties. The patterns of Fourier transformation infrared spectroscopy (FT–IR) and X-ray diffractometry (XRD) revealed that the SA, HDPE and CF were combined physically, and the crystal structure of the mixture remained constant. The results of scanning electronic microscopy (SEM) indicated that the microstructure of the CPCM was relatively stable. The results of differential scanning calorimetry (DSC) indicated that the melting point and latent heat of CPCM6 were 68.48 °C and 140.17 kJ/kg, and the solidifying point and latent heat were 66.95 °C and 141.09 kJ/kg. Thermal gravimetric analysis (TGA) verified that the CPCM had an improved thermal stability within the working temperature range. The thermal conductivity of CPCM6 was 0.4043 W/m⋅K, which is 2.22 times greater than for SA. The addition of CF effectively enhanced the thermal conductivity of the SA. Overall, CPCM6 possesses the potential for application in heat storage fields.