Preparation, characterization, and infrared emissivity property of optically active polyurethane/TiO_2/SiO_2 multilayered microspheres

摘要

Optically active polyurethane/titania/silica (LPU/TiO_2/SiO _2) multilayered coreshell composite microspheres were prepared by the combination of titania deposition on the surface of silica spheres and subsequent polymer grafting. LPU/TiO_2/SiO_2 was characterized by FT-IR, UVvis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), SEM and TEM, and the infrared emissivity value (814 μm) was investigated in addition. The results indicated that titania and polyurethane had been successfully coated onto the surfaces of silica microspheres. LPU/TiO_2/SiO_2 exhibited clearly multilayered coreshell construction. The infrared emissivity values reduced along with the increase of covering layers thus proved that the interfacial interactions had direct influence on the infrared emissivity. Besides, LPU/TiO_2/SiO_2 multilayered microspheres based on the optically active polyurethane took advantages of the orderly secondary structure and strengthened interfacial synergistic actions. Consequently, it possessed the lowest infrared emissivity value.