Expandable graphite is a flame retardant intumescent compound produced from natural flake graphite by a chemical or electrochemical treatment process. On exposure to high temperatures (typically >150°C), it expands volumetrically by as much as 100–450 times and changes from flat flakes to a “worm-like” porous structure. The expandable graphite is thus a char-forming flame retardant that insulates the material from heat, oxygen, and flame.
At Alfa Chemistry, our expandable graphite products maintain the desired qualities of graphite (thermal stability, chemical resistance, electrical conductivity) and feature low smoke toxicity, compressive resilience, self-sealing, etc. The products are eco-friendly, halogen-free flame retardants.
Expandable graphite (EG) is a chemically modified form of natural flake graphite, created through intercalation—typically using sulfuric acid—to insert molecules between its carbon layers. When heated, this structure enables dramatic volumetric expansion, transforming compact flakes into an accordion-like "worm" structure. Unlike conventional graphite, EG acts as an intumescent flame retardant, leveraging its unique expansion behavior to suppress fires.
When exposed to heat/flame:
We offer tailored formulations to meet diverse industrial needs.
| Catalog | Product Name | Expansion Start Temperature | Expansion Volume | Price |
|---|---|---|---|---|
| ACM7782425-178 | Expandable Graphite, EG-170-400 | 170 ℃ | 400 ml/g | Inquiry |
| ACM7782425-186 | Expandable Graphite, EG-175-150, 92% | 175 ℃ | ≥150 ml/g | Inquiry |
| ACM7782425-182 | Expandable Graphite, EG-175-350, 98% | 175 ℃ | ≥350 ml/g | Inquiry |
| ACM7782425-92 | Expandable Graphite, EG-175-350 | 175 ℃ | 350 ml/g | Inquiry |
| ACM7782425-187 | Expandable Graphite, EG-180-200, 90% | 180 ℃ | ≥200 ml/g | Inquiry |
| ACM7782425-188 | Expandable Graphite, EG-180-20, 94% | 180 ℃ | ≥20 ml/g | Inquiry |
| ACM7782425-185 | Expandable Graphite, EG-180-230, 95% | 180 ℃ | ≥230 ml/g | Inquiry |
| ACM7782425-184 | Expandable Graphite, EG-180-250, 95% | 180 ℃ | ≥250 ml/g | Inquiry |
| ACM7782425-183 | Expandable Graphite, EG-180-250, 99% | 180 ℃ | ≥250 ml/g | Inquiry |
| ACM7782425-179 | Expandable Graphite, EG-180-250 | 180 ℃ | 250 ml/g | Inquiry |
| ACM7782425-189 | Expandable Graphite, EG-180-35, 95% | 180 ℃ | ≥35 ml/g | Inquiry |
| ACM7782425-180 | Expandable Graphite, EG-250-180 | 250 ℃ | 180 ml/g | Inquiry |
| ACM7782425-181 | Expandable Graphite, EG-300-170 | 300 ℃ | 170 ml/g | Inquiry |
Ranging from 32 mesh (coarse) to 200 mesh (fine), optimized for dispersion in coatings, polymers, or fire-resistant foams.
| Catalog | Product Name | Price |
|---|---|---|
| ACMA00023501 | Normal expandable graphite, 32mesh | Inquiry |
| ACMA00023502 | Normal expandable graphite, 50mesh | Inquiry |
| ACMA00023503 | Normal expandable graphite, 80mesh | Inquiry |
| ACMA00023504 | Normal expandable graphite, 100mesh | Inquiry |
| ACMA00023505 | Normal expandable graphite, 150mesh | Inquiry |
| Catalog | Product Name | Expansion Volume | Price |
|---|---|---|---|
| ACMA00023510 | High purified carbon expandable graphite, 32mesh | 200-400 ml/g | Inquiry |
| ACMA00023511 | High purified carbon expandable graphite, 50mesh | 200-350 ml/g | Inquiry |
| ACMA00023512 | High purified carbon expandable graphite, 80mesh | 150-250 ml/g | Inquiry |
| ACMA00023513 | High purified carbon expandable graphite, 100mesh | 100-200 ml/g | Inquiry |
| ACMA00023506 | Ultralow sulphur expandable graphite, 32mesh | 200-400 ml/g | Inquiry |
| ACMA00023507 | Ultralow sulphur expandable graphite, 50mesh | 200-350 ml/g | Inquiry |
| ACMA00023508 | Ultralow sulphur expandable graphite, 80mesh | 150-250 ml/g | Inquiry |
| ACMA00023509 | Ultralow sulphur expandable graphite, 100mesh | 100-200 ml/g | Inquiry |
Consider these factors when choosing our expandable graphite:
At Alfa Chemistry, we deliver end-to-end support to optimize fire safety in your materials.
Custom Formulation Development
Performance Testing & Certification Support
We design and customize flame retardant systems with expandable graphite (EG) as a key ingredient:
Validate your materials in our advanced labs:
| Test Method | Parameters Measured | Reference Standards |
|---|---|---|
| Flammability | UL 94, LOI, cone calorimetry (HRR, THR) | ASTM D635, ISO 5660 |
| Smoke/Toxicity | Smoke density (ASTM E662), gas analysis | NFPA 269, EN 45545-2 |
| Corrosion Testing | Ionic contamination (Cl-, SO42-) | IPC TM-650 2.3.28 |
| Aging Resistance | Thermal cycling, UV/humidity exposure | ISO 4892, IEC 60068-2-30 |
Flame Retardant Performance Analysis
Thermal Analysis for Flame Retardant Materials
Toxicity Analysis of Flame Retardant Materials
Corrosive Analysis of Flame Retardant Materials
Expandable graphite delivers versatile fire protection across industries.
Intumescent seals for fire doors & windows, firestop pillows/pastes for cable/pipe penetrations, fireproof boards, sprayed coatings for structural steel, insulating foams (PIR/PUR), cementitious panels.
Function: Expands to form an insulating char layer, sealing openings and protecting structural elements from heat during a fire.
Flame retardant additive for thermoplastics (PP, PE, PA, EVA) and thermosets (epoxy, unsaturated polyester) used in housings, pipes, cable trays, automotive parts, electronics enclosures.
Function: Provides intumescent action within the polymer matrix, forming a protective char barrier that insulates and limits fuel/oxygen supply.
Flame retardant in cable sheathing/jacketing (especially halogen-free systems), electronic encapsulants, potting compounds, gaskets, battery pack components.
Function: Halogen-free flame retardancy; expands to create an insulating char layer that protects wires/components and prevents short circuits during fire.
Fire barrier materials for seats, headliners, carpets, insulation, and composite panels in aircraft, trains, buses, and ships. Engine compartment insulation.
Function: Meets stringent fire/smoke/toxicity regulations; forms an insulating char to delay fire spread and reduce toxic emissions.
Coating/binding for fire-resistant fabrics (curtains, tents, tarps, protective clothing), flexible foams (mattresses, furniture padding), nonwovens.
Function: Imparts intumescent properties, causing the fabric/foam to char and swell, forming a barrier against flame and heat.
Applications: Intumescent fire-protective coatings for structural steel (beams, columns), wood, and other substrates.
Function: When exposed to fire, the coating expands dramatically (intumesces) to form a thick, low-density, insulating char layer, protecting the underlying material.
Product: Ultralow Sulphur Expandable Graphite, 50mesh (Expansion: 180°C, 250×)
Challenge:
An automotive materials R&D department needed to develop a material that would prevent thermal runaway in battery packs and would not corrode aluminum components.
Our Solution:
Key Results:
Product: Expandable Graphite, EG-180-250, 99% (Sulphur-free)
Challenge: Encapsulating circuit boards required flame retardancy that wouldn't release corrosive gases.
Our Solution:
Key Results:
Product: Normal Expandable Graphite, 32mesh (Expansion: 250°C, 180×)
Challenge: Sealing flanges in chemical reactors (300°C service) needed compressible, fire-resistant material.
Our Solution:
Key Results:
High expansion ratio, wide heat treatment temperature range, fast activation, and versatility.
Adjust expansion temperature, particle size, and sulfur content.
From lab-scale testing to industrial scaling.
Advanced lab for UL 94, LOI, smoke density, corrosion.
Q: How does expandable graphite extinguish fires?
A: When heated, it expands into a vermicular char, which blocks oxygen diffusion, insulates unburned material, and releases inert gases to dilute combustibles.
Q: Is expandable graphite compatible with water-based coatings?
A: Yes! Specific EG specifications are available to meet these requirements. For example, surface-modified EG prevents precipitation and maintains pH stability (5–10). For custom functionalized EG, please contact our team.
Q: What loading % is typical for plastics?
A: Generally, 5–25% depending on the polymer. For example, PA6/EG formulations achieved the UL-94 V-0 rating with a wet sample loading of 20 wt% EG and a dry sample loading of 25 wt% EG.
Q: What factors should I consider when selecting expandable graphite?
A: Key considerations include expansion temperature, expansion ratio, particle size, sulfur content, purity and pH value, etc.
Q: What processing temperatures does expandable graphite support?
A: Different expandable graphite grades have different expansion temperatures, so we recommend processing at least 20°C below this temperature.
Q: Can expandable graphite be combined with other additives?
A: Yes! EG synergizes effectively with:
Custom formulations available at Alfa Chemistry. Learn more about the synergistic flame retardant systems of expandable graphite.
Q: Is expandable graphite environment friendly?
A: Yes, it is. Expandable graphite is frequently used as a non-halogen environmental-friendly flame retardant (FR) to replace conventional halogen FRs. Expandable graphite can also be used in environmental cleanup, e.g. for adsorption of pollutant, wastewater treatment, and so on.
Q: How is expandable graphite made?
A: Expanded graphite is prepared from natural flake graphite. The basic steps in its production include intercalation, washing, drying, and thermal expansion. The most important two are the intercalation and high-temperature expansion process. The purpose of intercalation is to prepare graphite intercalation compounds (GICs), which are further expanded to obtain the expanded graphite. The intercalation methods can be chemical oxidation, electrochemical oxidation, ultrasonic oxidation, vapor diffusion, etc.
Overview of two common industrial methods:
(Kim, Tae Young, et al., 2025)Kim, Tae Young, et al. recently synthesized a hydrophilic modified expandable graphite (mEG) from natural graphite (starting material), polymeric 4,4'-methylene diphenyl isocyanate (pMDI) (crosslinker), and polyethylene glycol (PEG) (surface modifier). The mEG showed superior hydrophilicity (contact angle 39.6° vs. 79.7° of unmodified EG). When incorporated into acrylic resin intumescent flame-retardant (IFR) coatings, mEG significantly improved fire resistance due to synergistic dispersion effects. The limited oxygen index (LOI) increased from 23% to 26%, while total heat release (THR) substantially decreased versus pure coatings. This performance enhancement resulted from mEG's uniform dispersion in the acrylic matrix, which promoted continuous char layer formation during combustion.
For tailored solutions or technical queries, just contact us!
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