PEG 400 Polyethylene Glycol 400 CAS 25322-68-3 Surfactant PEG 600 polyethylene glycol in Leather Auxiliary Agents
Classification:Chemical Auxiliary Agent
Other Names:Poly ethylene glycol
Grade: Pharmaceutical Grade
Place of Origin:ShenZhen, China (Mainland)
Usage:Coating Auxiliary Agents, Electronics Chemicals, Leather Auxiliary Agents, Paper Chemicals, Petroleum Additives, Plastic Auxiliary Agents, Rubber Auxiliary Agents, Surfactants, Textile Auxiliary Agents, Water Treatment Chemicals, heat carrier/solubilizing agent/plasticizing agent/thickening agent
Model Number:PEG 400
Water content(% m/m):≤0.5
Shell Life:two years
solubility:Soluble in water/organic solvent
Polyethylene glycol, or PEG for short, also macrogol in pharmacy, is a liquid or solid, water-soluble and non-toxic polymer with the general empirical formula C2nH4n + 2On + 1, depending on the chain length. Because of these properties, it is used in medicine, as a drug carrier in pharmacy, in industrial applications, in cell biology research and in cosmetic products. PEG has different properties depending on the chain length and the resulting molar mass.
The repeating unit of the linear polymer is (-CH 2 -CH 2 -O-), with a molar mass of about 44 g · mol-1. Chemically, it is a polyether.
For PEG with a mean molecular weight of 200 to 35,000 g / mol, the term polyethylene glycols has become common. Products with higher molecular weights (from about 35000 g / mol) are referred to as polyethylene oxide, since these products neglect the influence of the terminal hydroxyl groups. As an abbreviation, the term PEG or macrogol is used together with a numerical value indicating the average molecular weight.
Polyethylene glycols having an average molecular weight between 200 g / mol and 400 g / mol are non-volatile liquids at room temperature. PEG 600 has a melting range of 17 to 22 ° C and thus a paste-like consistency. At molecular weights above 3000 g / mol, the PEGs are solid substances and are sold as flakes or powders. Hardness and melting range increase with increasing molecular weight. By mixing a solid (PEG 1500) with a liquid PEG, a water-soluble product of ointment-like consistency can be prepared.
The most important property of all polyethylene glycols is their solubility in water. Liquid PEGs are miscible with water in any proportion. Even a PEG 8000 can still produce 50 percent solutions. This property is supported by the use of macrogol (PEG 3350) as a laxative.
The liquid PEGs are hygroscopic. The ability to absorb water decreases with increasing molecular mass.
Volatility and thermal stability
PEGs are non-volatile, a fact that is important in their use as plasticizers or humectants. At temperatures above 150 ° C, thermal decomposition occurs, which is associated with weight loss because of the volatile decomposition products. Applications at higher temperatures necessitate the use of antioxidants.
The polyethylene glycols have exceptionally low toxicity levels (acute and chronic oral toxicity, embryotoxicity, skin tolerance). They have therefore been used for decades in cosmetics, food and pharmaceutical preparations and are also listed in all relevant pharmacopoeias. The WHO has set a permitted daily dose of PEG in foods of 10 mg / kg body weight.
The biodegradability of the polyethylene glycols decreases with increasing average molecular weight. Until PEG 1500, however, they are considered biodegradable. The degradation of other substances is not affected by the PEG. Even 1 percent solutions are not toxic to fish and microorganisms. In Germany, the PEG are classified in water hazard class (WGK) 1. All polyethylene glycols can easily be thermally eliminated (burnt).
Preparation and restoration
With the help of PEG organic objects (fresh preparations, long wood soaked in water) can be converted to dry preparations. The originally moist objects (in water, alcohol or formalin) are either soaked for a long time or in a vacuum in a PEG solution. Thanks to the use of different PEG molecule sizes, most of the original liquid is replaced by the PEG. In the modern animal preparation, a mixing process is used due to the shrinking due to the drying, whereby classical methods of preparation are included.
In the paleontological preparation, subfossil fossils (for example, ice age finds) are treated with PEG. These fossils are very susceptible to climatic fluctuations and decompose z. B. by the resulting stresses during drying. Here we work only with a solid PEG-type, which replaces the water in the fossils via the path of diffusion. The PEG solidifies instead of the otherwise evaporating water and prevents the destructive tensions. The long-term experience with PEG preservation shows that this method promises the best results for this difficult-to-preserve material.