FRACTIONATION OF REACTIVE PERFLUOROPOLYOXYALKYLENE OLIGOMERS

Fractional distillation, solubility fractionation, and column chromatographic separation have been applied in the study of fractionation of perfluoropoly(oxymethylene-co-oxyethylene) oligomers with - CH2OH end units, containing mono and bifunctional species. With a suitable choice of conditions, all three techniques proved to be useful for the preparation of fractions with narrow molecular weight distribution. Column chromatography allowed the separation of fractions having, in addition, sharp mono and bifunctionality. On the basis of the experimental results, general indications for designing reactive oligomers fractionation procedures are discussed, prevalently centered on the copolymer end effect, which is typically present in this kind of compound. (C) 1995 John Wiley and Sons, Inc.