Preparation, characterization and infrared emissivity study of helical polyurethane@SiO2 core-shell composite

Helical polyurethane@SiO2 (HPU@SiO2) core-shell composite was prepared after surface modification of SiO2 nanoparticles. HPU@SiO2 was characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet (UV) spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate that the helical polyurethane has been successfully grafted onto the surfaces of the modified SiO2. HPU@SiO2 composite exhibits clearly core-shell structure. The ultraviolet absorption and crystallizability of HPU@SiO2 are changed due to the shell of helical polyurethane, which possesses regular single-handed conformation and inter-chain hydrogen bonds. The infrared emissivity of HPU@SiO2 was also investigated. The result indicates that the interfacial interactions between organic shell and inorganic core induce the infrared emissivity value being reduced from 0.781 for SiO2 to 0.503 for HPU@SiO2.