Effect of polyethylene glycol molecular weight on its performance

Polyethylene glycol is abbreviated as "PEG", cas 25322-68-3.It is a polymer compound made by intermolecular dehydration condensation of ethylene glycol. The chemical formula HOCH2(CH2OCH2)nCH2OH, where n is greater than 4. The average molecular weight is 200-7000, and the number after the commercial polyethylene glycol indicates the average molecular weight. For example, polyethylene glycol-400 means that the average molecular weight of this commercial polyethylene glycol is about 400. The properties vary according to the relative molecular mass, from a colorless and odorless viscous liquid to a waxy solid. Those with molecular weight of 200 to 600 are liquid at room temperature, and those with molecular weight of 600 or more gradually become semi-solid, and the properties vary with the average molecular weight. From colorless and odorless viscous liquid to wax-like solid. As the molecular weight increases, its moisture absorption capacity decreases accordingly.

Different molecular weight polyethylene glycols (PEG) have different physicochemical properties and application characteristics, so they have different uses.

Low molecular weight PEG (PEG200, PEG400, PEG600, PEG1000)

Low molecular weight PEG is usually liquid and has good solubility and lubricity, so it is often used as lubricant, skin moisturizer, transdermal accelerator, co-solvent, dye stabilizer, wetting agent, etc.

Medium molecular weight PEG (PEG2000,PEG4000,PEG6000,PEG8000,PEG10000)

Medium molecular weight PEG not only has lubricity and solubility, but also can be used as basic materials for the preparation of polymers, polymer modification, synthetic hydrogels, thickeners, etc.

High molecular weight PEG (molecular weight more than 10000)

High molecular weight PEG is usually solid and has the properties of high viscosity and high molecular weight. Due to its high molecular weight, it is commonly used in the preparation of polymer materials, such as polyurethane, polyamide, polyvinyl alcohol, etc. In addition, high molecular weight PEG can also be used as coating thickeners, textile coating agents, cosmetic base materials, etc.

It should be noted that the toxicity, pharmacokinetics and bioavailability of PEG may vary depending on its molecular weight, so care needs to be taken to select the appropriate molecular weight of PEG and to perform dose and safety control when applying it.