Concrete Additive Water Reducer Superplasticizer

2023-09-27

About types of Polyethylene glycol

2023-10-14

Polyethylene glycol (PEG) FAQs

What is polyethylene glycol？

Polyethylene glycol is a high molecular polymer with the chemical formula HO(CH2CH2O)nH. It is non-irritating, has a slightly bitter taste, has good water solubility, and has good compatibility with many organic components. It has excellent lubricity, moisturizing, dispersion and adhesion. It can be used as antistatic agent and softener in cosmetics, pharmaceuticals, chemical fibers, rubber, plastics, papermaking, paints, electroplating, pesticides, metal processing and food. It is widely used in processing and other industries

Physical and chemical properties of polyethylene glycol

Chemical structure

HO(CH2CH2O)nH is formed by the stepwise addition polymerization of ethylene oxide and water or ethylene glycol.

Chemical properties

The properties vary depending on the molecular weight, ranging from colorless and odorless viscous liquid to waxy solid. Those with a molecular weight of 200 to 600 are liquid at room temperature, and those with a molecular weight above 600 gradually become semi-solid. The properties also vary with the difference in average molecular weight. From colorless and odorless viscous liquid to waxy solid. As the molecular weight increases, its moisture absorption capacity decreases accordingly. This product is soluble in water, ethanol and many other organic solvents. Low vapor pressure, stable to heat, acid and alkali. Does not work with many chemicals. It has good hygroscopicity, lubricity and adhesion. Non-toxic and non-irritating. The average molecular weight is 300, n=5~5.75, the melting point is -15~8℃, and the relative density is 1.124~1.130. The average molecular weight is 600, n=12~13, the melting point is 20~25℃, the flash point is 246℃, and the relative density is 1.13 (20℃). The average molecular weight is 4000, n=70~85, and the melting point is 53~56℃.
Under normal conditions, polyethylene glycol is very stable, but it can react with oxygen in the air at temperatures of 120°C or higher. In an inert atmosphere (such as nitrogen and carbon dioxide), it will not change even if it is heated to 200~240°C. When the temperature rises to 300°C, thermal cracking will occur. Adding antioxidants, such as phenothiazine with a mass fraction of 0.25% to 0.5%, can improve its chemical stability. Any of its decomposition products are volatile and will not form a crusty or slimy sediment.
Polyethylene glycol is a polymer of ethylene oxide hydrolyzate. It is non-toxic and non-irritating and is widely used in various pharmaceutical preparations. Low molecular weight polyethylene glycol is relatively toxic. Overall, the toxicity of glycols is quite low. Topical application of polyethylene glycol, especially mucosal administration, can cause irritating pain. In topical lotions, it increases skin flexibility and has a moisturizing effect similar to that of glycerin. Diarrhea may occur after taking large doses. In injections, the maximum polyethylene glycol 300 concentration is about 30% (V/V), and hemolysis may occur at concentrations greater than 40% (V/V).
Addition polymer of polyethylene oxide and water. Those with a molecular weight below 700 are colorless, odorless, non-volatile, viscous liquids at 20°C, and are slightly hygroscopic. Those with molecular weights between 700 and 900 are semi-solid. Those with a molecular weight of 1,000 and above are light white waxy solids or flake-like paraffin wax or fluid powder. Miscible in water, soluble in many organic solvents, such as alcohols, ketones, chloroform, glycerides and aromatic hydrocarbons; insoluble in most aliphatic hydrocarbons and ether.
As the molecular weight increases, its water solubility, vapor pressure, water absorption and solubility in organic solvents decrease accordingly, while the freezing point, relative density, flash point and viscosity increase accordingly. It is heat stable, inert to many chemicals and does not hydrolyze.

Compatibility

Polyethylene glycol is a non-ionic water-soluble polymer. It is compatible with many highly polar substances and has poor compatibility with low-polarity substances. Polyethylene glycol with a low relative molecular weight has better compatibility. Polyethylene glycol can be compatible or partially compatible with oxidized starch, nitrocellulose, polyvinyl acetate and corn gluten. Incompatible with beeswax, castor oil, gelatin, gum arabic, mineral oil, olive oil and paraffin.

The main purpose of polyethylene glycol

Polyethylene glycol and polyethylene glycol fatty acid esters are widely used in the cosmetics and pharmaceutical industries. Because polyethylene glycol has many excellent properties: water solubility, non-volatility, physiological inertness, mildness, lubricity, and moisturizing, softness, and pleasant after-use feeling of the skin. Polyethylene glycol with different relative molecular weight fractions can be selected to change the viscosity, hygroscopicity and organizational structure of the product. Polyethylene glycol with low relative molecular weight (Mr<2000) is suitable for use as a wetting agent and consistency regulator for creams, lotions, toothpastes, shaving creams, etc. It is also suitable for non-wash hair care products. Gives hair a silky shine.
Polyethylene glycol with high relative molecular weight (Mr>2000) is suitable for lipstick, deodorant sticks, soaps, shaving soaps, foundation and beauty cosmetics, etc. In cleaning agents, polyethylene glycol is also used as a suspending agent and thickening agent. In the pharmaceutical industry, it is used as a base for ointments, emulsions, ointments, lotions and suppositories.
Polyethylene glycol is widely used in a variety of pharmaceutical preparations, such as injectables, topical preparations, ophthalmic preparations, oral and rectal preparations. Solid levels of polyethylene glycol can be added to liquid polyethylene glycol to adjust the viscosity for topical ointments; polyethylene glycol mixtures can be used as suppository bases; aqueous polyethylene glycol solutions can be used as suspending agents or to adjust other The viscosity of the suspension medium; the combination of polyethylene glycol and other emulsifiers can increase the stability of the emulsion. In addition, polyethylene glycol is also used as a film coating agent, tablet lubricant, controlled release material, etc.

Biomedical field applications

Medical polyethylene glycol is also known as polyethylene oxide (PEO). Linear polyether obtained by ring-opening polymerization of ethylene oxide. The main uses in the biomedical field are as follows:
1. Contact lens solution. The viscosity of polyethylene glycol aqueous solution is sensitive to shear rate and bacteria are not easy to grow on polyethylene glycol.
2. Synthetic lubricants. Condensation polymer of ethylene oxide and water. It is used as an ointment base for preparing water-soluble drugs, and can also be used as a solvent for acetylsalicylic acid, caffeine, nimodipine and other poorly water-soluble drugs for the preparation of injections.
3. Carrier for sustained release of drugs and immobilized enzymes. Coating the polyethylene glycol aqueous solution on the outer layer of the pill can control the diffusion of the drug in the pill in the body to improve the efficacy.
4. Surface modification of medical polymer materials. The biocompatibility of medical polymer materials in contact with blood can be improved by adsorbing, entrapping and grafting amphiphilic copolymers containing polyethylene glycol on the surface of medical polymer materials.
5. Make alkanol contraceptive membranes.
6. Make hydrophilic anticoagulant polyurethane.
7. Polyethylene glycol 4000 is an osmotic laxative, which can increase the osmotic pressure in the intestinal cavity, absorb water, soften the feces, increase the volume, and promote intestinal peristalsis and defecation.
8. Denture fixative. Polyethylene glycol is used as a component of denture fixatives due to its non-toxic and gel-forming properties.
9. PEG 4000 and PEG 6000 are often used to promote cell fusion or protoplast fusion and help organisms (such as yeast) take up DNA during transformation. PEG can absorb water in solutions, so it is also used to concentrate solutions.
10. In experiments to study protein molecules, the crowded environment in the body can be simulated to verify the impact of the crowded environment on the protein structure.

Other

Used as analytical reagents and also in the pharmaceutical industry;
Used in softeners, lubricants, etc.;
Used as matrix in medicines and cosmetics, and as dispersant, lubricant, emulsifier, etc. in rubber, metal processing, pesticide and other industries;
Medium for organic synthesis, humectants for daily cosmetics industry, inorganic salt solubilizers, viscosity regulators, etc.;
Used as flocculant, fluid friction reducer, textile sizing agent, retention and drainage aid, adhesive, thickener and denture fixative;
Used in cosmetics, pharmaceuticals, chemical fibers, rubber, papermaking, paints, and electroplating;
Used as molding agent, lubricant for metal wire drawing, stamping and forming, paper industry lubricant, cutting fluid, grinding fluid cooling lubrication, polishing agent, etc.;
Used as PVC lubricant, masterbatch additive, textile softener, pigment dispersant, etc.;
As a papermaking additive, it can improve the retention rate of fillers and fine fibers. When the relative molecular mass is above 3 million, it has good dispersion, certain wettability, drag reduction and pyrolysis properties. It is an effective deflocculant. Adding it to pulping can increase the viscosity of slurry, prevent fibers from adhering to each other, improve paper evenness, reduce pulping power consumption, and improve physical strength.

PEG-200：

It can be used as a medium for organic synthesis and a heat carrier with higher requirements. It can be used as a moisturizer, inorganic salt solubilizer and viscosity regulator in the daily chemical industry. It can be used as a softener and antistatic agent in the textile industry. It can also be used as a softener and antistatic agent in papermaking. Used as wetting agent in pesticide industry.

PEG-400：

PEG-400 is most suitable for making soft capsules. Since PEG400 is liquid, it has broad compatibility with various solvents and is a good solvent and solubilizer. It is widely used in liquid preparations, such as oral liquids, eye drops, etc. When vegetable oil is not suitable as a carrier for active ingredients, PEG is the material of choice. This is mainly because PEG is stable and does not deteriorate easily. Injections containing PEG are very safe and stable when heated to 150 degrees Celsius. In addition, it can be mixed with high molecular weight (PEG) and the mixture has good solubility and good compatibility with drugs.

PEG-400、600、800：

Used as a base for medicines and cosmetics, as a lubricant and wetting agent in the rubber and textile industries. PEG-600 is added to the electrolyte in the metal industry to enhance the grinding effect and enhance the luster of the metal surface.

PEG-1450、3350：

PEG-1450 and 3350 are most suitable for ointments, suppositories, and creams. Due to their high water solubility and wide melting point range, PEG1450 and 3350 can be used alone or mixed to produce a melting point range that has a long storage time and meets the requirements of drugs and physical effects. Suppositories using a PEG base are less irritating than those using traditional oil bases.

PEG-1000、PEG-1500：

It is used as a matrix, lubricant, and softener in the pharmaceutical, textile, and cosmetic industries; it is used as a dispersant in the coating industry to improve the water dispersion and flexibility of the resin, with a dosage of 10-30%; it can improve the stability of dyes in inks. It has solubility and reduces its volatility. It is especially suitable for wax paper and ink pad ink. It can also be used to adjust the ink viscosity in ballpoint pen ink. It can be used as a dispersant in the rubber industry to promote vulcanization and is used as a carbon black filler. Dispersant.

PEG-2000、3000：

Used as metal processing molding agent, lubricant and cutting fluid for metal drawing, stamping or forming, grinding, cooling, lubricating and polishing agent, welding agent, etc.; used as lubricant in the paper industry, and also used as hot melt adhesive to Increased rapid rewetting capability.

PEG-4000、6000、8000：

PEG-4000, 6000, and 8000 are used in tablets, capsules, film coatings, dropping pills, suppositories, etc.
PEG-4000 and 6000 are used as excipients in the pharmaceutical industry for the preparation of suppositories and ointments; as coating agents in the paper industry to increase the gloss and smoothness of paper; and as additives in the rubber industry to increase the lubrication of rubber products. properties and plasticity, reducing power consumption during processing and extending the service life of rubber products.
It is used as a matrix in the industrial production of medicine and cosmetics to adjust viscosity and melting point; it is used as a lubricant and coolant in the rubber and metal processing industries; it is used as a dispersant and emulsifier in the industrial production of pesticides and pigments; Used as antistatic agent, lubricant, etc. in the textile industry.
Due to the plasticity of PEG and its ability to improve drug release from tablets during the tableting process, high molecular weight PEG (PEG4000, PEG6000, PEG8000) is very useful as a binder for manufacturing tablets. PEG can make the surface of tablets shiny and smooth, while not easily damaged. In addition, a small amount of high molecular weight PEG (PEG4000, PEG6000, PEG8000) can prevent the adhesion between sugar-coated tablets and medicine bottles.

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