Methoxy polyethylene glycols are addition polymers of ethylene oxide and methanol, represented by the generalised formula CH3O-(CH2-CH2-O)n-H, with Œn¹ indicating the average number of oxyethylene groups.
In chemical abstracts methoxy polyethylene glycols are described under the scientific name Poly(oxy-1,2-ethanediyl)-a-methyl-w-hydroxy in combination with the CAS register number 9004-74-4. Other names are polyethylene glycol monomethyl ether and methoxy polyethylene glycol.
Methoxy polyethylene glycols are available in average molecular weights ranging from 350 to 5000. All MPEGs are designated by a number indicating the average molecular weight. MPEG 350 and 500 are clear viscous liquids at room temperature but MPEG 750 and 1000 require a temperature above 40°C. MPEG 2000, 3000 and 5000 are white waxy solids that are supplied in flake form. Some grades may also be supplied in molten form. For special product demands, information on applications or other special requirements contact the local sales office.
All MPEGs are soluble in many polar solvents as aliphatic ketones, alcohols, glycol ethers, esters and aromatic hydrocarbons. MPEGs are readily miscible with water, the solid MPEGs are slightly less soluble in water with their solubility decreasing as molecular weight increases.