The Effect of Polymer Dispersants on the Stability and Thermophysical Properties of Graphene Nanoplatelets/Alkane Composite Phase Change Materials

The phase change thermal management technology using solid–liquid phase change materials (PCMs) is the core technology for solving the problem of mismatch in the time, space and intensity of heat loads. The incorporation of graphene nanoparticles (GNPs) has been shown to enhance the heat transfer performance of PCMs. This study investigated the effects of polymer dispersants, specifically polyisobutylene succinimide (PIBSI), on the stability and thermal properties of nanocomposite phase-change material (NePCMs) made from GNPs and n-eicosane, a typical alkane PCM. The results indicate that the PIBSI dispersants, specifically the high molecular weight bispolyisobutylene succinimide T161, exhibit an excellent dispersion stability effect for GNPs in n-eicosane and are more effective than other types of dispersants. The dispersants primarily act through steric hindrance to disperse the GNPs in the non-polar alkane PCMs. Analysis of thermal conductivity revealed that greater stability of dispersion in the NePCMs correlates with higher thermal conductivity. However, using too much dispersant can reduce the thermal conductivity of NePCMs. The addition of dispersants into the NePCMs may lead to a decrease in total phase change enthalpy, attributable to the volume occupied by the dispersants within the NePCMs.