A stearic acid-based shape-stabilized phase change material supported by poly(vinyl alcohol)-modified branched polyethylene imine

Abstract

Preparing fatty acid-based shape-stabilized phase change materials (PCMs) by means of supporting materials is a practical method to address the leakage issue of pure fatty acids when used as PCMs. Herein, we prepared a stearic acid (SA)-based shape-stabilized PCMs using poly(vinyl alcohol) (PVA)-modified branched polyethylene imine (PEI) as the supporting material for the first time. SA is bonded with PEI by ionic bonds, while PEI is non-covalently combined with PVA through hydrogen bonding, giving rise to a structure similar to cross-linking that restricts the movement of the molecules of SA when the temperature rises above the melting point of SA. The chemical structure, phase change property, thermal reliability, thermal stability and crystalline morphology of the SA-based shape-stabilized PCMs were studied systematically in this paper. The results indicated that this novel PCMs exhibited suitable phase transition temperature in the range of 36.7–48.0 °C, with corresponding to the latent heats in melting and freezing process of 65.61 J g−1 and 61.75 J g−1, respectively. Thermogravimetric analysis and thermal cycling test showed that the prepared PCMs possess good thermal stability. It is concluded that the SA-based shape-stabilized PCMs has considerable potential for developing the role in thermal energy storage.