The physical and chemical properties

The physical form of polyethylene glycol can be from white mucous Mw200~700) to waxy semi-solid (Mw1000~2000), and then to hard waxy solid (Mw3000~20000). Polyethylene glycol is soluble in water and some common organic solvents. Liquid POLYETHYLENE glycol can be mixed with water in any proportion, while solid polyethylene glycol has a limited solubility, but even relatively high molecular weight polyethylene glycol has a solubility greater than 50 in water. When the temperature is high enough (PEG-6000.60℃), all grades of solid polyethylene glycol are soluble in water because their solubility is greatly improved. However, precipitation occurs in even thin solutions when the temperature is continuously raised close to the boiling point of water, depending on the relative molecular mass and concentration of the polymer. When polyethylene glycol is mixed with water, the volume shrinks slightly and the heat release is obvious.

Polyethylene glycol is very stable under normal conditions, but it can interact with oxygen in the air at temperatures of 120 ° C or higher. Even when heated to 200~240℃, inert atmosphere (such as nitrogen and carbon dioxide) does not change, and thermal cracking occurs when the temperature is raised to 300℃. The addition of antioxidants, such as meththiazide, with a mass fraction of 0.25 to 0.5, can improve its chemical stability. Any decomposition products are volatile and do not produce crusts or slime deposits.