Ultrasound irradiation prepare sulfur-free and lower exfoliate-temperature expandable graphite

The article reported a new way to prepare sulfur-free and lower exfoliate-temperature expandable graphite with ultrasound irradiation. Flake graphite mixture was used as raw material, sulfur-free inorganic and organic solvents were used as ultrasonic solvents. After ultrasound irradiation and wash, the expandable graphite was expanded at 350 °C to obtain sulfur-free expanded graphite. The process is the same as the preparation of sulfur-contain and high exfoliate-temperature expandable graphite with ultrasound irradiation. X-ray diffraction patterns were used to analyze the structure and confirm that the expandable graphite had been prepared. Scanning electron microscope images showed the structure of expandable graphite and the existence of expanded graphite.