Form-stable and tough paraffin-Al2O3/high density polyethylene composites as environment-friendly thermal energy storage materials: preparation, characterization and analysis

In this study, we focus on important global issue containing both environmental pollution control and energy saving. High density polyethylene (HDPE) is utilized as supporting material to load paraffin, while Al2O3 nano-powder is added into composite behaving as thermal conductivity enhancement to form composite phase change materials (paraffin-Al2O3/HDPE composite PCMs). By the adsorption test and differential scanning calomeritry (DSC) curves, the loading ratio of paraffin in paraffin/HDPE composite is 60%, via taking phase change enthalpy and thermal conductivity into integrated consideration, the adding ratio of Al2O3 is 3% in paraffin-Al2O3/HDPE composite. And CMT4304 universal tester results manifest paraffin-Al2O3/HDPE composites have high compressive strength. For paraffin-Al2O3/HDPE composite with 3 mass% Al2O3, Fourier transformation infrared (FT-IR) result indicates no chemical interaction among raw materials but physical combination. DSC results identify composite PCM happens solid–solid phase transition at 33.3 oC with enthalpy value of 10.7 J g−1 and melts at 48.8 oC with enthalpy value of 95.1 J g−1, and thermal cycling measurements demonstrate the form-stable composite PCM with adequate stability after 300 times melting/freezing cycles. Furthermore, the thermal conductivity of paraffin/HDPE composite is enhanced by 119.4% to attain 0.419 Wm−1 K−1 after addition of Al2O3. To sum up, form-stable and tough paraffin-Al2O3/HDPE composite PCMs look promising for application in building field as solar energy utilization materials.