Polyethylene Glycol (PEG)

Polyethylene Glycol (PEG) is a versatile, water-soluble polyether polymer composed of repeating ethylene oxide units. Identified by CAS No. 25322-68-3, PEG is available in a broad range of molecular weights, with its physical characteristics—including viscosity, melting point, solubility, and consistency—varying according to polymer chain length.

PEG is generally characterized by its excellent water solubility, low toxicity, chemical stability, lubricity, hygroscopicity, dispersibility, and compatibility with numerous organic and inorganic materials. These properties make it a valuable multifunctional ingredient in pharmaceutical, cosmetic, personal-care, chemical-processing, textile, and industrial formulations.

Depending on molecular weight and grade, PEG can function as a solvent, co-solvent, humectant, plasticizer, lubricant, dispersing agent, emulsification aid, viscosity modifier, binder, antistatic agent, softening agent, and formulation carrier.

Technical Specifications

Note: PEG is a polymer family rather than a single molecular species. Consequently, parameters such as molecular weight, melting point, viscosity, and physical form depend on the specified PEG grade (e.g., PEG 200, PEG 400, PEG 600, PEG 1000, PEG 4000, PEG 6000, PEG 8000).

Chemical Information

Common Synonyms and Commercial Designations

Polyethylene Glycol may be marketed under various nomenclatures and grade designations, including:

• Polyethylene Glycol

• Poly(Ethylene Glycol)

• Poly(Ethylene Oxide)

• Polyethylene Oxide (PEO)

• Poly(Oxyethylene)

• Macrogol

• PEG

• PEG 200

• PEG 400

• PEG 600

• PEG 1000

• PEG 4000

• PEG 6000

• PEG 8000

• Polyethylene Glycol Series

• Carbowax / Carb/Carbowax-type commercial designations

• Ethylene Glycol Polymer

• Polyethylene Oxide Standard

Specific commercial designations should always be matched to the corresponding molecular-weight grade and manufacturer specification.

Key Functional Properties

Polyethylene Glycol offers a combination of physicochemical properties that makes it suitable for a wide variety of formulations and processing applications:

• Excellent water solubility

• Broad solvent compatibility

• Good chemical stability

• Lubricating and slip-enhancing properties

• Moisture-retention and humectant functionality

• Dispersing and emulsification support

• Adhesion and binding properties

• Viscosity modification

• Plasticizing capability

• Antistatic performance

• Good film-forming and formulation compatibility

• Wide range of molecular-weight grades

• Adaptable solid, waxy, or liquid physical forms depending on grade

Applications

1. Pharmaceutical Industry

PEG is extensively utilized as a pharmaceutical excipient and formulation aid. Lower-molecular-weight grades can serve as solvents, co-solvents, solubilizers, humectants, and formulation stabilizers, while higher-molecular-weight grades are commonly used as ointment bases, suppository bases, binders, lubricants, carriers, and hydrophilic matrix-forming materials.

PEG grades such as PEG 4000 and PEG 6000 are particularly useful in the preparation of tablets, capsules, pills, microcapsules, and other dosage forms where controlled viscosity, hydrophilicity, lubrication, or matrix formation is required.

2. Cosmetics and Personal Care

PEG and PEG derivatives are widely used in cosmetic and personal-care formulations because of their water compatibility, moisturizing properties, lubricity, and ability to modify formulation texture and viscosity.

Depending on molecular weight and formulation requirements, PEG can function as a humectant, solvent, emulsion-supporting ingredient, viscosity modifier, softening agent, dispersant, and antistatic component.

3. Industrial and Chemical Processing

PEG is used as a multifunctional processing aid in numerous industrial applications. It can provide lubrication, dispersion, wetting, viscosity control, and surface-modification benefits, making it suitable for metalworking, polymer processing, coatings, adhesives, and specialty chemical formulations.

4. Textile Industry

PEG can be incorporated into textile-processing formulations as a lubricant, wetting agent, softening agent, antistatic additive, and processing aid. Its hydrophilic nature can contribute to improved handling and surface characteristics of treated materials.

5. Rubber and Polymer Processing

In rubber and polymer applications, PEG can function as a processing lubricant, dispersing agent, plasticizing aid, and formulation additive. Selected grades may improve the dispersion of fillers and other formulation components while contributing to processing efficiency.

6. Metalworking

PEG grades can be used in metalworking fluids, cutting formulations, stamping operations, mold-release systems, grinding processes, and polishing formulations. Their lubricating and water-compatible properties can support improved surface treatment and processing performance.

7. Agricultural and Specialty Formulations

PEG may be used as a dispersing agent, emulsification aid, carrier, or formulation additive in selected pesticide, agrochemical, pigment, and specialty chemical systems.

Molecular-Weight Grade Selection

The performance of PEG is strongly influenced by molecular weight:

• PEG 200–600: Predominantly liquid grades used as solvents, co-solvents, humectants, plasticizers, and formulation aids.

• PEG 1000–1500: Intermediate grades used in pharmaceutical, cosmetic, textile, and industrial formulations where increased viscosity and solidification characteristics are desirable.

• PEG 2000–3000: Higher-molecular-weight grades suitable for lubricating, processing, coating, and pharmaceutical applications.

• PEG 4000–6000: Solid or waxy grades commonly used as pharmaceutical excipients, lubricants, binders, dispersants, and processing aids.

• PEG 8000 and higher: High-molecular-weight grades used where increased viscosity, binding, film formation, or solid-state functionality is required.

Advantages

Polyethylene Glycol is particularly valued for its versatility and molecular-weight-dependent performance profile. By selecting an appropriate grade, formulators can tailor properties such as viscosity, melting behavior, water solubility, lubrication, binding, moisture retention, and dispersibility to meet specific application requirements.

Its broad compatibility and established use across pharmaceutical, cosmetic, chemical, textile, polymer, and industrial sectors make PEG a highly adaptable multifunctional material for modern formulation and manufacturing processes.

Product Handling and Specification Note

Because Polyethylene Glycol encompasses a broad family of molecular-weight grades, product specifications should be evaluated against the exact PEG grade being supplied. Parameters such as molecular weight, melting point, viscosity, pH, density, appearance, and application suitability may differ substantially between PEG grades.

For commercial, pharmaceutical, cosmetic, or industrial use, the applicable Certificate of Analysis (CoA), Safety Data Sheet (SDS), technical data sheet, and grade-specific specification should be consulted before use.