VERFAHREN ZUR EINENGUNG DER MOLKULARGEWICHTSVERTEILUNG VON POLYTETRAHYDROFURAN UND VON COPOLYMERISATEN AUS TETRAHYDROFURAN UND ALKYLENOXIDEN.

摘要

The mol. wt. distribution of polytetrahydrofuran (PTHF) and tetrahydrofuran/alkylene oxide copolymers is narrowed by (i) mixing the polymer with a solvent mixt. contg. (a) a 1-4C alkanol, (b) a 4-12C hydrocarbon and (c) water in which the individual components a, b and c lie between the limits 8-60 wt.%. (ii) sepg. the three phases from each other, (iii) isolating the polymer with the narrower mol. wt. distribution from the two lower phases. Pref. the alkanol is methanol or ethanol and the hydrocarbon is a 5-8C cycloaliphatic hydrocarbon, esp. cyclohexane or methylcyclohexane; the mixt. is prepd. at temps. of 0-80 deg.C and the wt. of solvent used is 2-6 times the wt. of polymer.