Patent ID: 6977045
Filing Date: 2005-12-20
Classification: C08G

Abstract:
1. A method for the fractionation of polyoxyalkylene polymers, comprising: a) dissolving up to about 10% by weight of polyoxyalkylene polymer in water to form a solution of a known concentration of polyoxyalkylene polymer; b) adjusting the temperature of the solution from step a) to a preselected temperature of between about −5° C. and 30° C.; c) adding about 5% to about 25% by weight of a salt to the solution of step b) to provide a known concentration of salt in the solution; and d) allowing the aqueous solution to form a high salt phase and a low salt phase at the preselected temperature; wherein the concentration of the polyoxyalkylene polymer, the concentration of the salt, and the preselected temperature are chosen so that the lower molecular weight polyoxyalkylene polymer molecules partition into the high salt concentration phase and the higher molecular weight polyoxyalkylene polymer molecules partition into the low salt concentration phase of the aqueous solution.