Universal supercritical binary mixture for polymer fractionation

Supercritical fluids are well known for their efficiency to fractionate polymers as a function of their molar mass, their architecture and their chemical composition, in the case of copolymers. We have used a supercritical solvent mixture, made of CO, and ethanol, to fractionate poly(ethylene oxide) (PEO) and polystyrene (PS). This mixture which can solubilize both polar (PEO) and nonpolar (PS) polymers, allows the obtention of a narrow molar mass distribution with possibility to select the molar mass value and the molar mass distribution of the extracted sample. The purification of a binary mixture of star and linear PEO has been also performed.