Polypropylene Glycol PPG 4000

Basic Information

Chemical Name: Polypropylene Glycol

Abbreviation: PPG 4000

CAS No.: 25322-69-4

Molecular Formula: HO-(C₃H₆O)ₙ-H (where "n" is the average degree of polymerization, corresponding to an average molecular weight of approximately 4000 g/mol)

Physical Properties

Appearance: White to off-white waxy solid at room temperature; melts into a clear, colorless to pale yellow liquid when heated.

Molecular Weight: Average 4000 g/mol (varies slightly by manufacturer, typically within ±5% of the nominal value).

Melting Point: Approximately 55-60°C (varies with molecular weight distribution).

Viscosity: When molten (at 75°C), viscosity ranges from 300-500 cSt (varies by grade).

Density: ~1.01 g/cm³ at 25°C (for molten state).

Solubility: Soluble in most organic solvents (e.g., ethanol, acetone, chloroform) and hydrophobic substances; insoluble in water but exhibits limited miscibility with water at higher temperatures.

Hygroscopicity: Low to moderate; absorbs minimal moisture from the air under normal conditions.

Chemical Properties

Non-ionic Nature: PPG 4000 is a non-ionic polyether, making it compatible with both ionic and non-ionic compounds.

Stability: Chemically stable under normal storage and handling conditions. Resistant to hydrolysis in neutral or weakly acidic environments; may degrade under strong acids or bases at elevated temperatures.

Reactivity: The terminal hydroxyl (-OH) groups allow for reactions with isocyanates, acids, or epoxides, enabling cross-linking or modification for use in polymer synthesis.

Thermal Stability: Decomposes at high temperatures (>200°C) under prolonged exposure, releasing harmless byproducts (e.g., water, carbon dioxide).

Product Characteristics

Low Toxicity: Generally recognized as safe (GRAS) for use in cosmetics, pharmaceuticals, and food-related applications (complies with relevant regulatory standards).

Lubricity: Exhibits good lubricating properties, making it suitable for formulations requiring reduced friction.

Emulsifying Ability: Functions as a mild emulsifier, helping stabilize oil-in-water or water-in-oil emulsions.

Moisturizing Properties: In personal care products, it helps retain moisture without a greasy feel.

Applications

Personal Care & Cosmetics: Used as a humectant, emollient, or viscosity modifier in creams, lotions, hair conditioners, and makeup. Its waxy texture at room temperature adds thickness to formulations.

Pharmaceuticals: Employed as a solubilizer, lubricant, or excipient in oral and topical medications. It aids in dissolving hydrophobic active ingredients and improving drug delivery.

Industrial Lubricants: Formulated into metalworking fluids, gear oils, and hydraulic fluids due to its lubricity and thermal stability.

Polymer Synthesis: Acts as a macrodiol in the production of polyurethanes (foams, elastomers, coatings) and polyester resins, contributing flexibility and durability to the final products.

Textile & Leather Industries: Used as a softener, antistatic agent, or lubricant for fibers and leather, enhancing texture and reducing friction.

Packaging & Storage

Packaging: Available in 25kg bags, 200kg drums, or bulk containers (IBCs) depending on quantity. Packaging materials are inert (e.g., HDPE, steel) to prevent chemical interaction.

Storage: Store in a cool, dry, well-ventilated area away from direct sunlight and heat sources. Keep containers tightly sealed to avoid moisture absorption. When stored properly, shelf life is typically 24 months.

Handling: Avoid prolonged skin contact (may cause mild irritation in sensitive individuals). Use gloves and protective eyewear when handling molten PPG 4000 to prevent burns.

PPG 4000 is valued for its versatility, combining the properties of polyethers with a high molecular weight to suit diverse industrial, pharmaceutical, and personal care applications.