Polypropylene glycol PPG-600 is a nonionic propylene oxide polymer whose chemical nature is a linear high-molecular-weight polyether compound formed by ring-opening polymerization of propylene oxide (C₃H₆O). The general molecular structure is HO(C₃H₆O)nH, where the degree of polymerization n≈10, indicating that the molecular chain consists of about 10 repeating units of propylene oxide, each end having an active hydroxyl group (—OH), making it a typical polyether diol structure. This double-terminal hydroxyl group structural feature makes it a core reactive intermediate for synthesizing polyurethane prepolymers, elastomers, and various surfactant derivatives.
The product contains ≥99% main component polypropylene glycol (solid content ≥99%), with moisture ≤0.1%, free alcohol ≤0.1%, acid value ≤0.1 mgKOH/g, and iodine value ≤1, indicating high purity and very few by-products. This high-purity index ensures excellent chemical stability and predictable reactivity in downstream reactions (such as condensation reactions with isocyanates), effectively avoiding product quality issues caused by impurities. The colorless to pale yellow appearance of the product also reflects its high-purity characteristics, making it suitable for use in cosmetics and pharmaceuticals where color sensitivity is important.
From a chemical classification perspective, the CAS number of polypropylene glycol PPG-600 is 25322-69-4, belonging to the poly(propylene glycol) series. Its molecular weight distribution is approximately 570~630, with a hydroxyl value of 178~197 mgKOH/g. These two parameters together determine its reactivity and performance, making it the counterpart product to polyethylene glycol (PEG-600) with a molecular weight specification of 600 in the polypropylene glycol series.
| Parameter Item | Specification Indicator |
|---|---|
| Chemical Name | Polypropylene Glycol (PPG-600) |
| CAS Number | 25322-69-4 |
| Molecular Formula | HO(C₃H₆O)nH, n≈10 |
| Molecular Weight | 570~630 |
| Effective Content | ≥99% |
| Hydroxyl Value | 178~197 mgKOH/g |
| Moisture | ≤0.1% |
| Acid Value | ≤0.1 mgKOH/g |
| Iodine Value | ≤1 |
| Appearance | Colorless to pale yellow viscous liquid |
| Ion Type | Nonionic |
Based on its main component—high-purity hydroxyl-terminated polyether diol—PPG-600 has important applications in the following fields: As a core synthetic raw material for polyurethane prepolymers and elastomers, providing flexible segments through reaction with isocyanates (such as TDI, MDI); As a basic component of industrial defoamers (in fermentation, papermaking, coatings), leveraging its low surface tension and low-foaming characteristics to quickly break foam; As a component of synthetic lubricant base oils and metalworking fluids, offering excellent lubricity and thermal oxidation stability; As a moisturizer in cosmetics and ointment base in pharmaceuticals, utilizing its mild skin-friendly properties and good biocompatibility.