Products Description
Expandable graphite powder is a special graphite material that has undergone chemical treatment. When exposed to high temperatures, it can expand rapidly to form a loose and porous worm-like structure, enabling its expansion volume to reach 100-400 times the initial volume. It is widely used in fields such as sealing, fire prevention, flame retardancy, and adsorption.
Key Performance Indicators
|
Parameter |
Typical Value |
Testing Standard |
|
Expansion Ratio |
100~400 mL/g (when heated at 900℃) |
GB/T 10698 |
|
Initial Expansion Temperature |
160~300℃ (depending on the intercalating agent) |
TGA/DSC Analysis |
|
Sulfur Content |
≤1000 ppm (≤200 ppm for low-sulfur type) |
ASTM D4239 |
|
pH Value |
5~7 (neutral) |
GB/T 1717 |
|
Fixed Carbon Content |
≥90% |
GB/T 3521 |
Note: Products support personalized customization.
Preparation of expandable graphite powder
(1) Selection of raw materials: High-quality high-purity graphite with a purity of over 99%, intercalating agents, and oxidizing agents.
(2) Production process: Intercalation reaction - Graphite is mixed with intercalating agents and soaked in special acid water. The mixture is soaked at 20-50℃ for 30-120 minutes to allow acid molecules to enter between the graphite layers, forming graphite intercalation compounds.
(3) Water washing/drying: Residual acid solution is removed, and the pH value is adjusted to 5-7 to avoid subsequent corrosion. Low-temperature drying is carried out at 60-80℃ to prevent premature expansion.
(4) Sieving: The final particle size is controlled to 80-300 mesh, which affects the expansion ratio.
Specific applications of expandable graphite powder
(1) Fireproof and flame-retardant materials Principle: It expands at high temperatures to form a heat-insulating carbon layer, isolating oxygen. Applications: Architectural fireproof coatings; cable flame-retardant tapes (replacing traditional halogen-based flame retardants); flame-retardant additives for polyurethane/epoxy resins (with an addition amount of 5-20%).
(2) Sealing materials Advantage: After expansion, it fills micropores, improving sealing performance. Applications: Gaskets for high-temperature pipeline flanges; engine cylinder gaskets (enabling them to withstand a temperature of 1600℃).
(3) Adsorbent materials Characteristic: After expansion, it has a large specific surface area and can adsorb oil stains and heavy metal ions.
Applications: Marine oil spill treatment; industrial wastewater purification.
(4) Other applications In terms of battery materials: Pre-expansion treatment for lithium battery anodes. For phase change energy storage materials: Enhancing their thermal conductivity. In military industry: Serving as anti-electromagnetic interference shielding layers.
Note:1. Wear gloves, mask and goggles to avoid contact/inhaling; rinse if skin contact occurs.
2.Keep away from heat (over 80°C may cause premature expansion) and open flames to prevent splashing.
3. Operate in ventilated area with dust removal to avoid long-term dust inhalation.
4. Do not mix with strong oxidants/alkalis.
5. Store sealed in dry place; avoid collision, high temperature and humidity during transportation.
6. Dispose as industrial waste; do not discard randomly.
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