Adjustable thermal property of polyethylene glycol/diatomite shape-stabilized composite phase change material

The work involves the fabrication, characterization, and thermal properties of polyethylene glycol (PEG)/diatomite powder (DP), which can be used as a novel shape-stabilized composite phase change material (CPCM). The maximum load of PEG in DP can reach 55% while PEG melts during solid-liquid phase transformation. Differential scanning calorimeter results indicated that the melting temperature of the new CPCMs could be adjusted from 34 to 59 degrees C and that the solidifying temperature could be adjusted from 27 to 44 degrees C. Corresponding latent heats of the melting and solidifying processes were 77.27-106.5 J/g and 72.07-94.93 J/g, respectively. Scanning electronic microscope, Fourier transform infrared spectroscopy, and X-ray diffraction results indicated that PEG was well dispersed in diatomite pores and no chemical changes took place during thermal cyclic test. Thermo-gravimetric analysis indicated that the CPCMs had good thermal and chemical stability and reliability when diatomite was immersed into melting PEG at 75 degrees C for 90 min. Thermal conductivity of the CPCMs increased from 0.36 to 0.71 W/mK after adding 10 wt% expanded graphite (EG). POLYM. COMPOS., 37:854-860, 2016. (c) 2014 Society of Plastics Engineers