Summary
Polymeric solid‐solid phase change materials (S‐SPCMs) are functional materials with phase transition‐heat storing/releasing ability. With this respect, a series of polyethylene glycol (PEG) grafted styrenic copolymer were produced as novel S‐SPCMs. PEGs with three different molecular weights were used for synthesis of isocyanate‐terminated polymers (ITPs). To achieve cross‐linking S‐SPCMs, the ITPs were grafted with styrene‐co‐ally alcohol) (PSAA) at three different PSAA:PEG mole ratios. The produced polymers were characterized using Fourier transform infrared (FT‐IR), proton nuclear magnetic resonance (1H NMR), and X‐ray diffraction (XRD) technique. The crystalline‐amorphous phase transitions of the polymers were examined using polarized optical microscopy (POM). The FT‐IR, NMR, and XRD results confirmed the expected chemical structures and crystallization performances of the polymers. Thermal energy storage (TES) properties of the S‐SPCMs were determined by differential scanning calorimetry (DSC). The DSC results revealed that the polymers with grafting ratio of PSAA:PEG(1:1) had phase transition enthalpies between about 74 and 142 J/g and phase transition temperatures between about 26°C and 57°C. Thermogravimetric analysis (TGA) measurements demonstrated that the S‐SPCMs were resistant to thermal decomposition until about 300°C. Thermal conductivities of the produced S‐SPCMs were measured in a range of about 0.18 to 0.19 W/mK. Furthermore, TES properties of the S‐SPCMs were slightly changed as their chemical structures were remained after 5000 thermal cycles. By overall evaluation of the findings, it can be foreseen that particularly PSAA‐g‐PEG(1:1) polymers can be considered as promising S‐SPCMs for some TES practices such as air conditioning of buildings, thermoregulation of food packages, automobile components, electronic devices, and solar photovoltaic panels.