PEG-180 ( PEG 8000)

PEG-180 ( PEG 8000) are a family of linear polymers formed by a base-catalyzed condensation reaction with repeating ethylene oxide units being added to ethylene. 
The molecular formula is (C2H4O)multH2O where mult denotes the average number of oxyethylene groups. 
The molecular weight can range from 200 to several million corresponding to the number of oxyethylene groups. 

CAS:    25322-68-3
MF:    (C2H4O)nH2O
EINECS:    500-038-2

Synonyms
1,2-ethanediol,homopolymer;2-ethanediyl),.alpha.-hydro-.omega.-hydroxy-Poly(oxy-1;Alcox E 160;Alcox E 30;alcoxe30;Poly(ethylene oxide),approx. M.W. 600,000;Poly(ethylene oxide),approx. M.W. 200,000;Poly(ethylene oxide),approx. M.W. 900,000

The higher-molecular-weight materials (100 000 to 5 000 000) are also referred to as polyethylene oxides. 
The average molecular weight of any specific polyethylene glycol product falls within quite narrow limits (°5%).
The number of ethylene oxide units or their approximate molecular weight (e.g., PEG-180 ( PEG 8000)) commonly designates the nomenclature of specific polyethylene glycols. 
Polyethylene glycols with amolecular weight less than 600 are liquid, whereas those of molecular weight 1000 and above are solid. 

These materials are nonvolatile, water-soluble, tasteless, and odorless. 
They are miscible with water, alcohols, esters, ketones, aromatic solvents, and chlorinated hydrocarbons, but immiscible with alkanes, paraffins, waxes, and ethers.
Any of several condensa-tion polymers of ethylene glycol with thegeneral formula HOCH2(CH2OCH2)nCH2OH orH(OCH2CH2)nOH. 
Average molecular weightsrange from 200 to 6000. 
Properties vary with molec-ular weight.
PEG-180 ( PEG 8000) is a polyethylene glycol that conforms to the general formula HO(CH2CH2O)nH, and is especially suited for the demands of the cosmetics industry, and is supplied in flakes. 
PEG-180 ( PEG 8000) has a density (70°C) of approx. 1.09 g/cm^3, a clear melting point of approx. 
63°C, and a flash point of approx. > 300°C. 
PEG-180 ( PEG 8000) is a water-soluble polyether alcohol that can be employed as a solubilizer and viscosity control agent in a variety of applications.

PEG-180 ( PEG 8000) Chemical Properties
Melting point: 64-66 °C
Boiling point: >250°C
Tg: -67
Bulk density: 400-500kg/m3
Density: 1.27 g/mL at 25 °C
Vapor density: >1 (vs air)
Vapor pressure: <0.01 mm Hg ( 20 °C)
Refractive index: n20/D 1.469
Fp: 270 °C
Storage temp.: 2-8°C
Solubility H2O: 50 mg/mL, clear, colorless
Form: waxy solid
Color: White to very pale yellow
Specific Gravity: 1.128
PH: 5.5-7.0 (25℃, 50mg/mL in H2O)
Biological source: synthetic (organic)
Water Solubility: Soluble in water.
λmax λ: 260 nm Amax: 0.6
λ: 280 nm Amax: 0.3
Sensitive: Hygroscopic
Merck: 14,7568
α-end: hydroxyl
Ω-end: hydroxyl
Stability: Stable. Incompatible with strong oxidizing agents.
LogP: -0.698 at 25℃
Surface tension: 43.5mN/m at 20°C
NIST Chemistry Reference: PEG-180 ( PEG 8000)(25322-68-3)
EPA Substance Registry System: PEG-180 ( PEG 8000) (25322-68-3)
Absorption: ≤0.1 at 280nm
≤0.2 at 260nm

PEG-180 ( PEG 8000) is a polymer which is hydrolyzed by ethylene oxide. 
PEG-180 ( PEG 8000) has no toxicity and irritation. 
PEG-180 ( PEG 8000) is widely used in various pharmaceutical preparations. The toxicity of low molecular weight polyethylene glycol is relatively large. 
In general, the toxicity of diols is very low. 
Topical application of PEG-180 ( PEG 8000), especially mucosal drug, can cause irritant pain. 
In topical lotion, this product can increase the flexibility of the skin, and has a similar moisturizing effect with glycerin. 
Diarrhoea can occur in large doses of oral administration. 
In injection, the maximum PEG-180 ( PEG 8000) concentration is about 30% (V/V). 
Hemolysis could occur when the concentration is more than 40% (V/V).

The USP32–NF27 describes polyethylene glycol as being an addition polymer of ethylene oxide and water. 
PEG-180 ( PEG 8000) are liquids; grades 1000 and above are solids at ambient temperatures.
Liquid grades (PEG 200–600) occur as clear, colorless or slightly yellow-colored, viscous liquids. 
They have a slight but characteristic odor and a bitter, slightly burning taste. 
PEG 600 can occur as a solid at ambient temperatures.
Solid grades (PEG>1000) are white or off-white in color, and range in consistency from pastes to waxy flakes. 
They have a faint, sweet odor. 
Grades of PEG-180 ( PEG 8000)PEG-180 ( PEG 8000) and above are available as freeflowing milled powders.

Uses    
PEG-180 ( PEG 8000) molecules of approximately 2000 monomers. 
PEG-180 ( PEG 8000) is used in various applications from industrial chemistry to biological chemistry. 
Recent research has shown PEG-180 ( PEG 8000) maintains the ability to aid the spinal cord injury recovery process, helping the nerve impulse conduction process in animals. 
In rats, PEG-180 ( PEG 8000) has been shown to aid in the repair of severed sciatic axons, helping with nerve damage recovery. 
PEG-180 ( PEG 8000) is industrially produced as a lubricating substance for various surfaces to reduce friction. 
PEG is also used in the preparation of vesicle transport systems in with application towards diagnostic procedures or drug delivery methods.
PEG-180 ( PEG 8000) is a binder, coating agent, dispersing agent, flavoring adjuvant, and plasticizing agent that is a clear, colorless, viscous, hygroscopic liquid resembling paraffin (white, waxy, or flakes), with a ph of 4.0–7.5 in 1:20 concentration. 
PEG-180 ( PEG 8000) is soluble in water (mw 1,000) and many organic solvents.
polyethylene glycol (PEG) is a binder, solvent, plasticizing agent, and softener widely used for cosmetic cream bases and pharmaceutical ointments. 
Pegs are quite humectant up to a molecular weight of 500. 
Beyond this weight, their water uptake diminishes.
Used in conjunction with carbon black to form a conductive composite.
Polymer nanospheres of poly(ethylene glycol) were used for drug delivery.

Application in biomedicine    
PEG-180 ( PEG 8000) is also known as polyoxirane (PEO). 
PEG-180 ( PEG 8000) is a linear polyether obtained by ring opening polymerization of ethylene oxide. 
The main uses in the field of biomedicine are as follows:
Contact lens liquid. 
The viscosity of PEG-180 ( PEG 8000) solution is sensitive to the shear rate and it is not easy for bacteria to grow on polyethylene glycol.
Synthetic lubricants. 
The condensation polymer of ethylene oxide and water. 
PEG-180 ( PEG 8000) is a cream matrix for preparing water-soluble drugs. 
PEG-180 ( PEG 8000) can also be used as a solvent for acetylsalicylic acid and caffeine, which is difficult to dissolve in water.
Drug sustained-release and immobilized enzyme carrier. 
The PEG-180 ( PEG 8000) solution is applied to the outer layer of the pill to control the diffusion of drugs in the pill so as to improve the efficacy.
Surface modification of medical polymer materials. 

The biocompatibility of medical polymer materials in contact with blood can be improved by adsorption, interception and grafting of two amphiphilic copolymers containing polyethylene glycol on the surface of medical polymers.
PEG-180 ( PEG 8000) can make the membrane of the alkanol contraceptive pill.
PEG-180 ( PEG 8000) can make hydrophilic anticoagulant polyurethane.
PEG-180 ( PEG 8000) is an osmotic laxative. 
PEG-180 ( PEG 8000) can increase osmotic pressure and absorb moisture in the intestinal cavity, which makes the stool soften and increase in volume, resulting in bowel movement and defecation.
Denture fixing agent. 
Peg nontoxic and gelatinous nature can be used as a component of denture fixer.
PEG-180 ( PEG 8000) is commonly used to promote cell fusion or protoplast fusion and help organisms (such as yeasts) to take DNA in transformation. 
PEG-180 ( PEG 8000) absorbs water from the solution, so it is also used to concentrate the solution.

Production Methods    
PEG-180 ( PEG 8000) polymers are formed by the reaction of ethylene oxide and water under pressure in the presence of a catalyst.