Microencapsulated pentadecane with nanocrystalline cellulose reinforced silane-acrylate shell for cold thermal energy storage application

The microencapsulated phase change material (MEPCM) contains n-pentadecane as core material and nanocellulose-reinforced silane-acrylate (NVS) as shell material synthesized by emulsion polymerization. Vinyl tri-methoxy silane (VTMS)-modified nanocellulose was used as a crosslinker (X-linker). The effect of novel crosslinking agent concentration on the phase change properties of microcapsules was examined. The pentadecane/NVS (MEPCMs) were analyzed by Fourier transform infrared spectroscopy (FT-IR), optical microscopy (OM), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that microcapsules were synthesized successfully, and the best performance was obtained in MEPCM at 16% X-linker loading in shell composition. FT-IR indicates that there are no chemical reactions between the core and shell of the MEPCMs. The optical micrograph shows that with an increasing amount of silane acrylate-based X-linker in the emulsion recipe, the size of the MEPCM agglomerate was increased. The average diameter of MEPCM at 16% X-linker content is 0.5–2.6 μm investigated by SEM. The encapsulation efficiency and enthalpy of phase change of the MEPCM increase with X-linker contents. For MEPCM, the highest phase change enthalpy is 75.72 J/g with a maximum encapsulation efficiency of 58.8% at 16% X-linker content calculated by DSC parameters. This study is practically helpful for the development of thermoregulating composite materials.