Preparation of porous titanium dioxide foam impregnated with polyethylene glycol as shape-stable composite phase change materials

In this work, a novel shape-stabilized composite phase change material, was prepared by using high porosity and uniform, open, controllable, 3D interconnected porous titanium dioxide foam (PTF) as the package carrier material and polyethylene glycol (PEG) as phase change material. The heat storage performance and non-isothermal crystallization process of prepared composite phase change material were further studied and the effect of 3D fully interconnected pore structure of PTF on the phase change behavior and thermal conductivity of PEG were also further investigated. The DSC results indicated that the enthalpy of melting and solidification of the PEG-PTF were 145.9 and 142.9 J/g, respectively, and the corresponding actual impregnation ratio (φ) reached 70%. Because PTF porous matrix provides abundant crystallization sites during PEG solidification process, the inhibition effect of matrix on PEG phase transformation is significantly alleviated, which is demonstrated by the decrease in DH value. Non-isothermal crystallization results showed that the activation energy of PEG (−2.67 kJ/mol) was higher than that of PEG-PTF (−2.19 kJ/mol) but the half crystallization time of PEG was similar with that of PEG-PTF, which indicated that the 3D fully interconnected pore structure of PTF partially eliminated the inhibition effect of porous carrier on PEG phase transformation behavior. The results of XRD, FT-IR, thermal cycle and TGA tests showed that PEG-PTF composite phase change material had good chemical compatibility, thermal reliability, and thermal stability. This study showed that the PTF was a novel and promising support material for the preparation of PEG composite phase change materials.