Question

What are the main ingredients of Polyethylene Glycol PEG-400?

Answer
2026-05-17 官方文档 聚乙二醇PEG-400

Polyethylene Glycol PEG-400 is a high molecular weight polymer formed by the gradual addition polymerization of ethylene oxide with water or ethylene glycol, with the molecular formula expressed as HO(C₂H₄O)nH (n≈4~14), belonging to nonionic surfactants.

Detailed Explanation

Polyethylene Glycol PEG-400 (CAS No.: 25322-68-3) is mainly composed of polyoxyethylene glycol, a high molecular weight polymer obtained by ring-opening polymerization of ethylene oxide as monomer and water or ethylene glycol as initiator. According to the Guoli Chemical Product Database, its general molecular formula is HO(C₂H₄O)nH, with the degree of polymerization n ranging approximately from 4 to 14, thereby controlling the average molecular weight of the product between 380 and 420. The appearance is a colorless transparent viscous liquid, with excellent chemical stability and wide compatibility.

The active ingredient content of this product is ≥99.5%, belonging to a high purity grade polyethylene glycol product. The remaining trace components include water (≤0.5%), free alcohol (≤0.5%), and trace acid (acid value ≤0.5 mgKOH/g) and other impurities, all strictly controlled to ensure product quality. Due to the high controllability of the ethylene oxide polymerization process, this product has a narrow molecular weight distribution and stable batch-to-batch performance, meeting the strict requirements of high-end application fields such as pharmaceutical excipients and daily chemical raw materials.

As a nonionic high molecular surfactant, the molecular chain of PEG-400 contains a large number of ether bonds (-C-O-C-) and terminal hydroxyl groups (-OH), which determine its excellent hydrophilicity — it is soluble in polar solvents such as water, ethanol and acetone in any proportion. It is this unique molecular structure that endows the product with outstanding solubilization, wetting, dispersibility, and moisturizing and lubricating properties, making it an indispensable raw material widely used in industrial and pharmaceutical fields.

Technical Parameters

Parameter ItemSpecification / Description
Chemical NamePolyethylene Glycol 400 (Polyoxyethylene Glycol 400)
CAS No.25322-68-3
Ion TypeNonionic
General Molecular FormulaHO(C2H4O)nH, n≈4~14
Average Molecular Weight380~420
Active Content (Purity)≥99.5%
AppearanceColorless transparent viscous liquid
Water Content≤0.5%
Hydroxyl Value264~300 mgKOH/g
Acid Value≤0.5 mgKOH/g
pH Value (1% Aqueous Solution)4.5~7.5
HLB ValueTheoretical value about 20
Density (25°C)1.11~1.13 g/cm³
Kinematic Viscosity (25°C)90~120 mm²/s
Freezing PointAbout 4~8°C

Application Recommendations

Based on real data from the Guoli Chemical Database, the purity of PEG-400 is as high as 99.5% or more, making it suitable for pharmaceutical, daily chemical, and industrial fields with strict requirements on raw material purity. In pharmaceutical preparations, it can be used as a water-soluble base for ointments and suppositories, a solubilizer for injections, and a carrier for dropping pills; in daily chemical products, it plays an efficient moisturizing and lubricating role; in the textile industry, it is used as an antistatic agent and a component of soft finishing agents. The specific dosage should be determined by formulation experiments. It is recommended that users conduct sufficient compatibility and stability tests before application.

Precautions

  • This product is hygroscopic. It should be sealed immediately after opening to avoid quality degradation due to prolonged exposure to air.
  • Storage temperature is recommended to be controlled between 5°C and 30°C. Solidification may occur in low temperature environments (freezing point about 4~8°C). Slight heating can restore the transparent liquid state without affecting product quality.
  • Avoid contact with strong oxidizers and strong acids to avoid dangerous reactions.
  • Although this product is a non-hazardous chemical and has no serious irritation to skin and eyes, it is still recommended to wear protective gloves and goggles during operation and maintain good ventilation.