Non-isothermal crystallization behavior of Ag nanoparticles modified expanded graphite/paraffin composite phase change material

Abstract

The thermal conductivity enhancement fillers and supporting material have significant influence on the crystallization process of phase change materials (PCMs) in composite PCMs. In this work, the non-isothermal crystallization behavior of Ag nanoparticles modified expanded graphite/paraffin (AEP) composited PCMs was studied to analyze the effect of expanded graphite (EG) and Ag nanoparticles on the crystallization process of paraffin wax (PW). The results showed that non-isothermal crystallization parameters of t1/2 and F(T) and activation energy of 0-AEP was lower than those of PW, indicating that the crystal growth and nucleation of PW were accelerated by EG. After Ag nanoparticles were modified, the t1/2 and F(T) and the activation energy of AEP were increased which were higher than that of 0-AEP but still lower than that of pure PW, revealing that the crystal growth and nucleation of PW were restricted by the surface interaction between Ag and PW. The non-isothermal crystallization analysis results provide a valuable reference for deeply understanding phase change behavior and kinetics of the CPCMs.