Different molecular weight structures of polyethylene glycol and its application fields
With the continuous expansion of the application field of polyethylene glycol, the production of polyethylene glycol in countries and regions such as Europe, America and Japan has increased rapidly. There are various types of polyethylene glycol products in foreign countries. The structure of poly(ethylene glycol) is HOCH2[CH2OCH2] nCH2OH or H[ OCH2CH2] nOH is a general term for ethylene glycol polymers having an average molecular weight of 200 to 8000 or more. With the difference in average molecular weight, the properties also vary. From colorless and odorless viscous liquids to waxy solids, toxicity decreases with increasing molecular weight, and polyethylene glycol with a molecular weight of 4000 to 8000 is safe for humans. The hydroxyl groups at both ends of polyethylene glycol have primary alcohol properties, especially for esterification and etherification reactions. The reaction product of low molecular weight polyethylene glycol is easy.Mixed with the oil, the reaction product of the high molecular weight polyethylene glycol tends to be water soluble. When heated in air, polyethylene glycol is oxidized. Polyethylene glycol is soluble in water and alcohols, esters, glycol ethers, etc., and is insoluble in aliphatic hydrocarbons. As a phase transfer catalyst, polyethylene glycol has been widely used. It has a helical structure, can be folded into holes of different sizes, can be complexed with ions of different radii to carry out phase transfer catalysis reaction, and can be used as Williamson phase. The catalyst is transferred and the operation is extremely convenient. Polyethylene glycol is water-soluble and has excellent solubility properties for a variety of drugs, and is widely used as a carrier for ointment bases and active ingredients. Solid polyethylene glycol can be used as a water-soluble suppository base. Polyethylene glycol has wide compatibility. It can be used as a vehicle and binder for many pharmaceutical preparations. Polyethylene glycol has a compatibilizing effect and is suitable for various high quality. Production of cosmetics. Polyethylene glycol can also be used as a non-greasy lubricant, a softener in anti-static agents and an antistatic agent, and an emulsification aid for soap. After cross-linking, polyethylene glycol absorbs 10 to 100 times its own weight of water. It can be released when necessary, and can be used as a super absorbent resin by utilizing this property. Polyethylene glycol can also be used for reusable water packaging films and medical bandages. Polyethylene glycol can form associative complexes with many substances, such as phenolic resin, lignin derivatives, polycarboxylic acids, polyesters, etc., and the complex formed expands its application in new fields.