Application of calcium tetra borate and barium tetra borate nanoparticles as flame retardant in the preparation of flame resistant polyester fiber nanocomposite

In this research, flame retardant polymer-nanocomposites with polyester fibers and inorganic nano materials were prepared to investigate the reduction of flammability. Nano calcium tetraborate (CaB4O7) and Nano barium tetraborate (BaB4O7) were synthesized by precipitation method onto polyester fibers to achieve flame retardant fiber nanocomposite. The prepared fiber nanocomposites were characterized by several techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), fourier transform infrared spectroscopy (FT-IR), vertical flammability test, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The CaB4O7 and BaB4O7 with less than 100 nm in size, was found to be well-dispersed throughout the matrix without the formation of large aggregates which is showed efficient flame-retardancy properties. The optimum values for donation of flame-retardancy were obtained 8.02 and 9.5% for calcium tetra borate and barium tetra borate, respectively. TGA/DTG and DSC analysis of pure, treated fibers was accomplished and their thermograms were compared and commented. The results show that the flame retardancy mechanism of obtained flame retardant coated fiber is a condensed-phase phenomenon due to the formation of a protective char layer that acts as a mass transport barrier and a thermal insulator.