Preparation and properties of capric acid-stearic acid-based ternary phase change materials.

Two kinds of CA-SA-based ternary phase change materials (PCMs), namely, capric acid-stearic acid-palmitic acid (CA-SA-PA) and capric acid-stearic acid-octadecanol (CA-SA-OD), were prepared by the melting-blending method. By the step cooling curve method, the optimum mass ratio of the two PCMs were determined to be CA : SA : PA = 77.4 : 8.6 : 14.0 and CA : SA : OD = 81.9 : 9.1 : 9.0, and the crystallization temperatures were 19.20 °C and 23.90 °C, respectively. The phase transition temperatures as measured by DSC were 18.60 °C and 24.82 °C, and the latent heat of phase transition were 129.15 J g and 161.74 J g, respectively. The results are in good agreement with those measured by the step cooling curve method. The chemical and crystalline properties of the two PCMs were analyzed by FT-IR and XRD. It was found that CA-SA is combined with PA or OD by physical action, and the components have good compatibility and form a good eutectic structure. In addition, the results of heat storage and heat release experiments and the 500 times of accelerated melting-solidification cycling test showed that the two kinds of PCMs have good heat resistance and thermal reliability. Therefore, the prepared CA-SA-PA and CA-SA-OD have good performance and great application potential in building energy saving and solar energy utilization.