Microencapsulated phase change materials with TiO2-doped PMMA shell for thermal energy storage and UV-shielding

Microcapsules with thermal energy storage and UV-shielding functions were successfully prepared by the method of suspension-like polymerization in order to reduce the damage of ultraviolet light. The bifunctional microcapsules (MPCMs/TiO2) consist of n-octadecane as core material and poly (methyl-methacrylate) (PMMA) doped with titanium dioxide nanoparticles as shell material. The scanning electronic microscope (SEM) micrographs and particle size distributions showed that the as-prepared microcapsules are spherical and about 10-20 µm in average diameter. It was confirmed by Fourier transformation infrared spectroscope (FTIR) and energy dispersive spectrometer (EDS) spectra that modified TiO2 nanoparticles had been well fixed in the cross-linked network structure of PMMA shell. In addition, the results of differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA) and ultraviolet visible spectrophotometer (UV-vis) measurements demonstrated that the microcapsules exhibited high thermal storage capability, good thermal reliability and stability, and good UV-shielding property. The resultant samples of MPCMs/TiO2 may become the potential materials in the advanced applications of intelligent textile.