Preparation of Expandable Graphite and Its Flame Retardant Properties in HDPE Composites

This study showed an efficient and novel way to prepare expandable graphite (EG) which is one kind of halogen-free flame retardant using the O-3-hydrothermal process. The results showed the expanded volume of EG using the O-3-hydrothermal process was higher than those compared to convectional liquid phase synthesis, ultrasound irradiation and hydrothermal method. X-ray diffraction pattern, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to analyze the structure and confirm that EG had been prepared. Scanning electron microscope was utilized to observe the morphology of EG and char from HDPE/O-3-HEG composites. Cone calorimeter, limiting oxygen index, and UL-94 were used to investigate the flame retardant property of the HDPE/O-3-HEG composites and showed the HDPE/O-3-HEG composite possesses excellent flame retardant property. (C) 2015 Society of Plastics Engineers