Optimization of super water-retention phase change gels for cold energy storage in cold chain transportation

A eutectic hydrated salt (EHS) formed by disodium hydrogen phosphate dodecahydrate (DHPD) and sodium carbonate decahydrate (SCD) was used as the cold energy storage functional medium, and then the nucleating agent sodium pyrophosphate decahydrate (SPD), the phase change temperature regulators ammonium sulfate (N) and potassium sulfate (K) were added to prepare a sample DSSNK5, and by adding superabsorbent polymer (SAP), a phase change gel DSSNK5-SAP was finally obtained. The results show that the phase change temperature of DSSNK5-SAP is 7.71 °C, and its latent heat value is 122.1 J g⁻¹, which remains unchanged after 50 cycles. Compared with pure DHPD, the supercooling degree of DSSNK5-SAP is reduced to 3 °C, and the thermal conductivity is 1.5 times that of DHPD. In addition, the crystal structure and chemical compatibility of DSSNK5-SAP were analyzed, and the regulation mechanism of auxiliaries and SAP on the phase change behavior of EHS was described. The cold energy storage/release and transient response performance of DSSNK5-SAP were tested, and the application experiment of fruit preservation was also carried out. As a result, DSSNK5-SAP can make the fruit have a good fresh-keeping effect, which proves its considerable application potential in cold chain transportation. It reduces the cost of cold chain transportation from the root and contributes to the stable development of the city and society.