Patent ID: 8604159

Claim:
A method for forming a functionalized polymer, comprising: (a) functionalizing HO-POLY-OH polymers in a substantially pure composition of HO-POLY-OH polymers to effect the introduction of one or more of the same functional group, Y, onto HO-POLY-OH under conditions effective to form from 8 to 45 percent of monosubstituted polymers of the formula HO-POLY-L-Y, no more than 40 percent of disubstituted polymers of the formula Y-L-POLY-L-Y, and about 65 to 91 percent of the unsubstituted HO-POLY-OH, and wherein no other functional group other than the functional group Y functionalizes the HO-POLY-OH polymers; and (b) purifying to provide a composition comprising monosubstituted polymers of the formula HO-POLY-L-Y substantially free from the unsubstituted polymers of the formula HO-POLY-OH and disubstituted polymers of the formula Y-L-POLY-L-Y, wherein POLY is a water-soluble and non-peptidic polymer, Y is a functional group in protected or unprotected form, and L is a linking group.