Abstract: In this study, a chemically cross-linked polymer network system based on polyethyleneimine (PEI) and glycerol triglycidyl ether (GTE) was constructed. Using this system as a matrix, erythritol (ERY) phase change composites with controllable heat release behavior were prepared, and the regulatory mechanism of the polymer network on the supercooling stability and crystallization behavior of ERY was systematically investigated. The results show that the polymer network interacts with ERY through physical interactions, and ERY maintains its original crystal structure within the network. Notably, the increase in cross-linking density of the polymer network leads to a decrease in the cold crystallization temperature, which contradicts conventional theoretical expectations, as a higher cross-linking density implies an increase in -OH groups within the network that should enhance interactions with ERY and thereby increase the cold crystallization temperature. Further analysis reveals that intramolecular hydrogen bonds formed among the -OH groups within the polymer network competitively weaken the effective interactions between the network and ERY molecules, thereby promoting its intrinsic crystallization behavior. This study provides a new perspective and experimental basis for in-depth understanding of the regulation of intermolecular interactions on the phase change thermodynamic behavior in ERY-based composite phase change materials.

Key words: Erythritol, Phase change materials, Controllable phase change materials; Molecular interactions, Polymer networks