WE CLAIM:
1. A method comprising the step of alkoxylating in a suitable solvent a previously isolated alkoxylatable oligomer to form an alkoxylated polymeric material, wherein the previously isolated alkoxylatable oligomer has a known and defined weight-average molecular weight of greater than 300 Daltons.
2. The method of claim 1 , wherein the previously isolated alkoxylatable oligomer has a known and defined weight-average molecular weight of greater than 500 Daltons.
3. The method of claim 1, wherein both the previously isolated alkoxylatable oligomer and the alkoxylated polymeric product are soluble in the suitable solvent.
4. The method of claim 1, wherein the previously isolated alkoxylatable oligomer is prepared by (a) alkoxylating a precursor molecule having a molecular weight of less than 300 Daltons to form a reaction mixture comprising an alkoxylatable oligomer, and (b) isolating the alkoxylatable oligomer from the reaction mixture.
5. The method of claim 1, where the alkoxylation utilizes ethylene oxide as an alkoxylation agent.
6. The method of claim 4, wherein the precursor molecule is selected from the group consisting of glycerol, diglycerol, triglycerol, hexaglycerol, mannitol, sorbitol, pentaerythritol, dipentaerthitol, and tripentaerythritol.
7. The method of claim 1, wherein both the previously isolated alkoxylatable oligomer and the alkoxylated polymeric product each has from one to eight primary hydroxyl groups.
8. The method of claim 7, wherein each of the one to eight primary hydroxyl groups is the result of an alkoxylation reaction.
9. The method of claim 7, wherein the neither the previously isolated alkoxylatable oligomer and the alkoxylated polymeric product has a hydroxyl group of the precursor molecule.

10. The method of claim 1, wherein both the previously isolated alkoxylatable oligomer and the alkoxylated polymeric product each has a branched structure.
11. The method of claim 10, wherein the branched structure is a 4- to 8-arm branched structure.
12. The method of claim 11, wherein the branched structure is a 4-arm branched structure.
13. The method of claim 11, wherein the branched structure is a 5-arm branched structure.
14. The method of claim 11, wherein the branched structure is a 6-arm branched structure.
15. The method of claim 11, wherein the branched structure is an 8-arm branched structure.
16. The method of claim 1, wherein the previously isolated alkoxylatable oligomer has the following structure:

wherein the average value of n within the structure is from 2 to 50.
17. The method of claim 1, wherein the alkoxylated polymeric material has the following
structure:

wherein the average value of all the instances of n within the structure is from 10 to 1000.

18. The method of claim 1, wherein the previously isolated alkoxylatable oligomer has
the following structure:

wherein the average value of all instances of the value of n within the structure is from 2 to 35.
19. The method of claim 1, wherein the alkoxylated polymeric material has the following
structure:

wherein the average value of all instances of the value of n within the structure is from 10 to 750.
20. The method of claim 1, wherein the previously isolated alkoxylatable oligomer has
the following structure:

wherein the average value of all instances of the value of n within the structure is 2 to 35.

21. The method of claim 1, wherein the alkoxylated polymeric material has the following
structure:

wherein the average value of all instances of the value of n within the structure is 10 to 600.
22. The method of any one of claims 17, 19 and 21, wherein the average value of all instances of the value of n within the structure is from 50 to 400.
23. The method of any one of claims 17, 19 and 21, wherein the average value of all instances of the value of n within the structure is from 50 to 300.
24. The method of any one of claims 16 through 23, wherein all values of n are within three standard deviations of each other.
25. The method of any one of claims 16 through 23, wherein all values of n are within two standard deviations of each other.
26. The method of any one of claims 16 through 23, wherein all values of n are within one standard deviation of each other.
27. The method of claim 1, wherein the suitable solvent include organic solvents selected from the group consisting of tetrahydrofuran (THF), dimethyl formamide (DMF), toluene, benzene, xylenes, mcsitylene, tetrachloroethylene, anisole, and mixtures of the foregoing.
28. The method of claim 1, wherein the suitable solvent is selected from the group consisting of toluene, xylene, mesitylene, tetrahydrofuran (THF), and mixtures of foregoing.

29. The method of claim 1, wherein the suitable solvent is toluene used in quantities that after ethoxylation the solvent consists more than 25 wt% and less than 75 wt% of the reaction mixture.
30. The method of claim 1, wherein the step of alkoxylating is carried out under alkoxylating conditions, wherein the alkoxylation conditions include the presence of a strong base.
31. The method of claim 30, wherein the strong base is selected from the group consisting of one or more alkali metals.
32. The method of claim 30, wherein the strong base is selected from the group consisting of metallic potassium, metallic sodium, sodium-potassium alloys, and a hydroxide.
33. The method of claim 32, wherein the hydroxide is NaOH, KOH and mixtures thereof.
34. The method of claim 32, wherein the strong base is a sodium-potassium alloy.
35. The method of claim 30, wherein the strong base is an alkoxide of a previously isolated alkoxylatable oligomer.
36. The method of claim 30, wherein the strong base is present in a catalytic amount.
37. The method of claim 36, wherein the catalytic amount is from 0.001 to 10.0 weight percent strong base based upon the weight of the total reaction mixture.
38. The method of claim 36, wherein the catalytic amount is from 0.01 to about 6.0 weight percent strong base based upon the weight of the total reaction mixture.
39. The method of claim 1, wherein the step of alkoxylating is carried out under alkoxylating conditions wherein the amount of water present is less than 20 ppm.

40. The method of claim 39, wherein the step of alkoxylating is carried out under alkoxylating conditions wherein the amount of water present is less than 14 ppm.
41. The method of claim 40, wherein the alkoxylating step is carried out under alkoxylating conditions wherein the amount of water present is less than 8 ppm.
42. The method of claim 1, wherein the alkoxylating step is carried out at a temperature between 80 °C and 140 °C.
43. A composition comprising the alkoxylated polymeric product prepared in accordance with the method of any one of claims 1 to 42.
44. The composition of claim 42, wherein the purity of the alkoxylated polymeric product is greater than 92 wt % and the total content of high molecular weight impurities and diols is less than 8 wt %.
45. The composition of claim 44, wherein the purity is greater than 98 wt % and the total content of high molecular weight impurities and diols is less than 2 wt%.
46. The method of any one of claims 1 to 42, further comprising the step of modifying the alkoxylated polymeric material to bear a reactive group to thereby form a water-soluble polymer reagent.
47. The method of claim 46, wherein the water-soluble polymer reagent has the following structure: