Calcium Borate Nanomaterials Preparation, Characterization And Flame Retardancy

Fire prevention, elimination of disasters, it is an eternal human theme of social security. In recent years, major fires continue to occur throughout the world, which endanger the lives of people, and cause the damage of property. The environmental pollution resulted from fire is becoming more and more serious. Therefore, the application of flame retardant materials has attracted worldwide attention. At the same time, people also pay much more attention to environmental protection issues. Low-toxic, efficient and smoke suppression of inorganic flame retardant are completely complianced with the current trend of development of flame-retardant materials, and its prospect will be very optimistic.Calcium borate with high thermal stability, non-toxic, etc., is an effective and inexpensive inorganic flame retardant. However, the calcium borate particles are hardly dispersed in the matrix, which restrains their uses in industry. Besides the sizes and the morphologies of the fire retardant also greatly affect its flame retardant property. But so far, the preparation of calcium borate nano-structures and investigation of their flame retardant properties are rarely reported. Therefore, the synthesis, characterization and property of flame retardant about calcium borate nano materials are of very important practical significance.In this paper, two kinds of calcium borate forα-4CaO·5B2O3·7H2O and 2CaO·B2O3·H2O nano-structures have been prepared by hydrothermal methods, which were characterized by X-ray powder diffraction (XRD), X-ray spectroscopy (EDS), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Details are as follows:(1) The spherical-, silkworm chrysalis-like a-4CaO·5B2O3·7H2O nanostructure constructed by nanoflake have been synthesized under hydrothermal conditions at 120℃with Na2B4O7·10H2O and Ca(NO3)2·4H2O as raw materials, using water and ethanol as mixture solvent; by adding hexamethylenetetramine, a-4CaO·5B2O3-·H2O nanoflake have been prepared. The influences of reaction temperature, reaction time, solvent and surfactant, etc. on the morphology and size of calcium borate a-4CaO·5B2O3·7H2O have also been investigated by many groups of comparison test.(2) Calcium borate 2CaO·B2O3·H2O nanobelts and sectorial 2CaO·B2O3·H2O nanostructure constructed by nanobelts have been synthesized under hydrothermal conditions at 180℃with CaCl2, H3BO3 and NaOH as raw materials. The influences of reaction temperature, reaction time, pH value and surfactant, etc. on the morphology and size of calcium borate of 2CaO·B2O3·H2O have also been investigated by many groups of comparison test. (3) The flame retardant properties of the prepared a-4CaO·5B2O3·7H2O and 2CaO·B2O3·H2O nanostructures were investigated by the thermal analysis method.The experiments show that the type, the morphology and the size of samples have been influenced by the different raw materials, reaction temperature, reaction time, pH value, solvent, surfactant and other factors. The smaller solvent concentration, more conducive to the formation of nanostructures. The size of nanostructure is more smaller, the morphology is more uniform, and the flame retardant property will be more better. The flame retardant tests showed that the prepared calcium borate nanomaterials have more better performance than the non-nanostructure sample. These results establish an experimental foundation for the fire retardant property of calcium borate nano materials.