Paraffin/expanded graphite phase change composites with enhanced thermal conductivity prepared by implanted β-SiC nanowires with chemical vapor deposition method

Expanded graphite/beta-SiC nanowires composites (ESNC) were prepared through chemical vapor deposition, and paraffin/expanded graphite/beta-SiC nanowires composites (PESNC) were made through vacuum impregnation to overcome liquid leakage during phase transition and enhance the thermal conductivity of paraffin. Fourier transform infrared spectroscopy showed no chemical interactions between the paraffin and ESNC. Differential scanning calorimetry estimated the temperature and latent heat of PESNC during melting to 45.73 degrees C and 124.31 J g(-1), respectively. The respective values of these quantities during freezing were recorded as 48.93 degrees C and 124.14 J g(-1). The thermal conductivity of PESNC was estimated to 0.75 W mK(-1), which was 3.26-folds that of pure paraffin (0.23 W mK(-1)). PESNC perfectly maintained its phase transition after 200 melting-freezing cycles. The resulting ideal thermal conductivity, good chemical stability, thermal properties and thermal reliability of PESNC are promising for use in energy efficient buildings and solar energy systems.