The form-stable phase change materials based on polyethylene glycol and functionalized carbon nanotubes for heat storage

Form-stable phase change materials (PCMs) for heat storage based on polyethylene glycol (PEG) and functionalized multi-wall carbon nanotubes (MWNTs) were prepared via a blending and impregnating method. The structural and thermal properties of the as-prepared PCMs were analyzed by various techniques. The phase change temperatures and enthalpies of the composite PCMs with hydroxylated (-OH), carboxylated (-COOH) and aminoated (-NH₂) MWNTs (PEG/MWNT-x PCMs) are lower than those with pristine MWNTs (PEG/MWNT PCMs). The influence of functional groups on the phase change behavior of the composite PCMs follows the order of: MWNT-COOH > MWNT-NH₂ > MWNT-OH > MWNT. Capillary forces, surface areas and hydrogen bonding are mainly influential on the phase change behavior of PEG/MWNT-x PCMs.