Polypropylene glycol PPG-400 (CAS: 25322-69-4) appears as a colorless to slightly yellow transparent viscous liquid with the molecular formula HO(C3H6O)nH (n≈6.7) and a molecular weight range of 380~420. The product is synthesized by catalytic polymerization of propylene oxide and propylene glycol. Its molecular structure contains primary hydroxyl groups and ether bonds, endowing it with unique solubility and reactivity. This product is classified as a nonionic surfactant with an HLB value of about 2.0, exhibiting low foaming characteristics in water and a cloud point of approximately 50°C (1% aqueous solution).
In terms of physical properties, PPG-400 has a density of 1.004~1.010 g/cm³, refractive index of 1.450~1.452 (25°C), kinematic viscosity of approximately 70 mm²/s (40°C), and low shear viscosity of about 70 mPa·s. Its melting point is below -30°C, flash point ≥200°C, and it is chemically stable, resistant to acids, alkalis, and hard water media. The product is readily soluble in water, alcohols, esters, ketones, and other organic solvents, with low hygroscopicity and excellent compatibility with a variety of organic solvents, resins, and polymers.
Regarding chemical indicators, the product has an active content ≥99%, moisture ≤0.1%, acid value ≤0.1 mgKOH/g, saponification value ≤0.5 mgKOH/g, iodine value ≤0.1 gI2/100g, amine value ≤0.1 mgKOH/g, unsaturation ≤0.1 mmol/g, free alcohol ≤0.1%, heavy metals ≤10 mg/kg, and arsenic ≤2 mg/kg. These parameters indicate high purity and low impurity content of PPG-400, making it suitable for applications with strict quality requirements such as polyurethane synthesis, pharmaceuticals, and personal care fields.
| Parameter Item | Specification | Remarks |
|---|---|---|
| Appearance | Colorless to slightly yellow transparent viscous liquid | Visual inspection |
| CAS Number | 25322-69-4 | — |
| Molecular Formula | HO(C3H6O)nH, n≈6.7 | — |
| Molecular Weight | 380~420 | — |
| Ionic Type | Nonionic | — |
| HLB Value | Approximately 2.0 | Low hydrophilic-lipophilic balance |
| Active Content | ≥99% | — |
| Moisture | ≤0.1% | — |
| pH Value (1% Aqueous Solution) | 6.0~8.0 | — |
| pH Value (5% Aqueous Solution) | 5.0~7.0 | — |
| Density | 1.004~1.010 g/cm³ | 25°C |
| Refractive Index | 1.450~1.452 | 25°C |
| Kinematic Viscosity | Approximately 70 mm²/s | 40°C |
| Low Shear Viscosity | 70~90 mPa·s | 25°C |
| Cloud Point | Approximately 50°C | 1% Aqueous Solution |
| Flash Point (Closed Cup) | ≥200°C | — |
| Melting Point | <-30°C | — |
| Surface Tension | Approximately 38 mN/m | 1% Aqueous Solution |
| Hydroxyl Value | 260~300 mgKOH/g | — |
| Acid Value | ≤0.1 mgKOH/g | — |
| Saponification Value | ≤0.5 mgKOH/g | — |
| Iodine Value | ≤0.1 gI2/100g | — |
| Amine Value | ≤0.1 mgKOH/g | — |
| Unsaturation | ≤0.1 mmol/g | — |
| Free Alcohol | ≤0.1% | — |
| Heavy Metals | ≤10 mg/kg | — |
| Arsenic | ≤2 mg/kg | — |
| Solubility | Readily soluble in water, alcohols, esters, ketones, and other solvents | — |
| Foam Characteristics | Low foaming | — |
| Chemical Stability | Stable (resistant to acids, alkalis, and hard water) | — |
| Packaging Specifications | 50kg plastic drum / 200kg plastic drum / IBC tote | — |
Based on the physicochemical properties of PPG-400, it is recommended for the following key applications: