Polyethylene Glycol PEG-400 (CAS No.: 25322-68-3) is a high-molecular polymer produced by the stepwise addition polymerization of ethylene oxide with water or ethylene glycol. Its molecular structure is HO(C₂H₄O)nH, where n≈4~14, and the average molecular weight is between 380 and 420. This product is a nonionic surfactant, appearing as a colorless transparent viscous liquid, readily soluble in polar solvents such as water, ethanol, and acetone, and has good hygroscopicity.
In terms of physicochemical properties, PEG-400 has an HLB value of approximately 20, belonging to highly hydrophilic surfactants. The surface tension of a 1% aqueous solution is about 63 mN/m (25°C), and the cloud point is greater than 100°C (1% aqueous solution). The product has a relatively low solidification point, around 4~8°C, and may solidify or precipitate under low temperature conditions, which can be restored to a transparent state after appropriate heating. Its kinematic viscosity at 25°C is 90~120 mm²/s, low shear viscosity is about 110 mPa·s, density is 1.11~1.13 g/cm³, refractive index (nD²⁰) is in the range of 1.466~1.468, and open-cup flash point is ≥200°C, making it a high-flash-point substance that is not easily flammable at room temperature.
PEG-400 has stable chemical properties and can be stably used under general alkaline conditions, but contact with strong oxidants should be avoided. The product has low foam characteristics and is not a type of surfactant prone to foaming. It should be noted that this product has no critical micelle concentration (CMC) parameter and does not contain amine value, tertiary amine, phosphate ester, etc. In addition, due to the strong hygroscopicity of PEG-400, the container must be kept sealed during storage and use to avoid prolonged exposure to air, which may lead to quality degradation.
| Parameter Name | Technical Index |
|---|---|
| CAS No. | 25322-68-3 |
| Chemical Name | Polyethylene Glycol 400 / Polyoxyethylene Glycol 400 |
| Molecular Formula | HO(C₂H₄O)nH, n≈4~14 |
| Average Molecular Weight | 380~420 |
| Appearance | Colorless transparent viscous liquid |
| Ion Type | Nonionic |
| Active Content | ≥99.5% |
| Solid Content | ≥99% |
| Moisture Content | ≤0.5% |
| Density (25°C) | 1.11~1.13 g/cm³ |
| Kinematic Viscosity (25°C) | 90~120 mm²/s |
| Low Shear Viscosity (25°C) | Approx. 110 mPa·s |
| Refractive Index (nD²⁰) | 1.466~1.468 |
| Solidification Point | Approx. 4~8°C |
| Flash Point (Open Cup) | ≥200°C |
| pH Value (1% Aqueous Solution) | 4.5~7.5 |
| pH Value (5% Aqueous Solution) | 4.5~7.5 |
| HLB Value | 20 |
| Cloud Point (1% Aqueous Solution) | >100°C |
| Surface Tension (1% Aqueous Solution, 25°C) | Approx. 63 mN/m |
| Hydroxyl Value | 264~300 mgKOH/g |
| Acid Value | ≤0.5 mgKOH/g |
| Saponification Value | ≤1 mgKOH/g |
| Iodine Value | ≤1 gI₂/100g |
| Free Alcohol | ≤0.5% |
| Heavy Metals | ≤10 mg/kg |
| Arsenic | ≤2 mg/kg |
| Solubility | Readily soluble in water, ethanol, acetone |
| Hygroscopicity | Easily hygroscopic |
| Foam Characteristics | Low foam |
| Critical Micelle Concentration (CMC) |