Novel gelatinous shape-stabilized phase change materials with high heat storage density

A series of polyol acetal derivatives were synthesized through condensation reactions of aromatic aldehyde with polyols, including sorbitol, mannitol, xylitol, and pentaerythritol. They were examined as gelators in the formation of paraffin-based shape-stabilized phase change materials (PCMs), in which 1,3:2,4-di-(4-methyl) benzylidene sorbitol (MDBS) exhibited excellent thermal stability. Three-dimensional netted structural phase change materials were obtained by paraffin doped with different gelators, which were thermally stable so that no leakage of paraffin occurs even under higher temperature than the melting point of paraffin. It was found that PCMs doped with 3 wt% expanded and exfoliated graphite (EG) exhibited better thermal conductivity, similar phase change temperature and heat storage density.

From the contrast of the two types PCMs showed in the figure, it could be easily found that the gelatinous shape-stabilized PCMs had the advantage at the higher maximum ratio of paraffin without leakage of paraffin. When the content of MDBS was 3–5 wt%, the paraffin leakage of gelatinous PCM was as much as that of paraffin–HDPE PCM with about 20 wt% content of HDPE.Figure optionsDownload as PowerPoint slideResearch highlights
► In this paper, we conducted a synthesis study to prepare low molecular-weight organic gelators, which can gel organic liquid with low concentrations (typically<2 wt%) of gelators.
► By introducing ball-drop method and some other methods to study paraffin-based PCMs in this work we evaluated the gelators' potential in forming shape-stabilized paraffin-based PCMs.
► By introducing proper polyol acetal derivatives as gelator into paraffin, we prepared novel gelatinous shape-stabilized PCMs with high heat storage density. This may open a way to enhance the heat storage density of paraffin-based PCMs.