Preparation and characterization of polyethylene glycol/active carbon composites as shape-stabilized phase change materials

Shape-stabilized phase change materials (PCMs) composed of polyethylene glycol (PEG) and mesoporous active carbon (AC) were prepared by a blending and impregnating method. Various techniques were carried out to characterize the structural and thermal properties of the composites. Lower phase change temperatures and enthalpies were observed as the weight percentage and molecular weight of PEG was decreased. The crystallinity of PEG in the PCMs decreased with the increase in the AC content. The activation energy of the PEG phase change decreased with higher PEG weight percentages. We conclude that the phase change properties of the PEG/AC PCMs are influenced by the adsorption confinement of the PEG segments from the porous structure of AC and also the interference of AC by acting as an impurity with perfect PEG crystallization.