Polyethylene glycol (PEG) is a colorless, odorless, water-soluble, hydrophilic polymer with the chemical formula:HO(CH2CH2O)nH Depending on its molecular weight, it can be in liquid or waxy solid form and has wide applications in pharmaceuticals, cosmetics, food, and chemicals. It is mainly used as a solvent, thickener, lubricant, humectant, pharmaceutical excipient (such as laxatives and sustained-release carriers), and cultural relic preservation agent. It possesses good biocompatibility and biodegradability, making it a reliable green material. 

Main properties

· Solubility : Soluble in water and many organic solvents, but insoluble in aliphatic hydrocarbons.

· Physical state : Low molecular weight (such as PEG400) is liquid, and high molecular weight (such as PEG1000 and above) is waxy solid.

· Chemical stability : Thermally stable and not easily hydrolyzed.

· Biocompatibility : Non-toxic, low immunogenicity, and suitable for human use.

· Special property : It can form hydrogels with high water content. 

Main applications

· In the pharmaceutical field :

       Excipients : Used in the production of tablets, soft capsules, suppositories, oral liquids, etc., to improve drug solubility and bioavailability.

       Laxatives , such as PEG3350, soften stool by absorbing water and treat constipation.

Drug delivery : PEGylation enhances drug solubility, stability, and pharmacokinetics.

Medical devices : materials used for surgical adhesion, hemostasis, and anti-adhesion; tissue engineering scaffolds.

· Cosmetics : Used as a moisturizer, lubricant, and softener.

· Chemical Industry : Lubricants, antistatic agents, surfactants, heat transfer fluids, gas chromatography stationary phases.

· Cultural relic preservation : It replaces moisture, stabilizes water-soaked wood and painted pottery figurines, and prevents them from drying out and cracking.

· Other : Food processing (as a carrier).