PEG-400

Polyethylene Glycol 400 (PEG-400) is a low molecular weight, transparent, colorless, and nearly odorless viscous liquid with an average molecular weight of approximately 380–420 g/mol. It belongs to the class of nonionic polymers. Its typical physical properties include a dynamic viscosity of approximately 90-110 cP at room temperature (25°C), a freezing point between 4-8°C, and significant hygroscopicity, enabling it to absorb moisture from the environment. PEG-400 exhibits excellent solubility and compatibility, being miscible with water, alcohols, glycerin, and most polar solvents in any proportion. It serves as an effective co-solvent to enhance compatibility between aqueous phases and numerous organic components, though it has extremely low solubility in aliphatic hydrocarbons.

Chemically stable, it resists weak acids, weak bases, and electrolytes, with favorable toxicological data (oral LD₅₀ > 30,000 mg/kg). It complies with USP/NF, EP, FDA, and other international pharmacopoeia and food additive standards.

It is commonly used as a water-based lubricant and release agent in rubber, plastic, and metal processing; as a non-volatile plasticizer in coatings, adhesives, and sealants to enhance film flexibility and durability. In the textile processing industry, it serves as a fiber softener and antistatic agent, improving fabric hand feel and processing properties.

Gasoline is added to a reactor, and aluminum isopropoxide is added as a catalyst (catalyst amount: 1.01%–1.03% of the total monomer amount) under stirring. After replacing the air in the reactor with nitrogen, ethylene oxide monomer is added (solvent:ethylene oxide = 2:chemical book 1, mass ratio). The reaction is carried out at 10–20°C for 4 hours. Then, the temperature is gradually increased to 35–40°C, and the reaction is carried out for another 3 hours. After the polymerization reaction is completed, the material is transferred to a distillation vessel to distill off the solvent, cool to crystallize, filter, and obtain the crude product. Vacuum drying yields the finished product.

Polyethylene glycol (PEG) is a nonionic, water-soluble polymer. It is compatible with many highly polar substances, but has poor compatibility with low-polarity substances. Lower molecular weight PEGs generally have better compatibility. PEG can be compatible or partially compatible with proteins, oxidized starch, nitrocellulose, polyvinyl acetate, and zein. It is immiscible with beeswax, castor oil, gelatin, gum arabic, mineral oil, olive oil, and paraffin wax.