Patent attributes
A method of making a pure block copolymer includes forming a crude block copolymer; heating a solution of the crude block copolymer and alcohol; and cooling the solution to promote precipitation of a purified block copolymer, wherein an amount of impurities remaining in the purified block copolymer is from about 0 to about 5 wt % based on a total weight of the purified block copolymer; a ratio of a polydispersity index of the crude block copolymer to a polydispersity index of the purified block copolymer is from about 1.02 to about 1.25; a ratio of a molecular weight of the crude block copolymer to a molecular weight of the purified block copolymer is from about 0.75 to about 1.0; and a ratio of a number average molecular weight of the crude block copolymer to a number average molecular weight of the purified block copolymer is from about 0.65 to about 1.
