| 摘要 |
The object of the present invention is a method for changing the predefined mean molecular weight Mn during the continuous production of polytetrahydrofurane, or tetrahydrofurane copolymers, the monoesters or diesters of polytetrahydrofurane, or tetrahydrofurane copolymers, by the polymerization of tetrahydrofurane in the presence of telogen and/or a comonomer on an acid catalyst, wherein: a) the mol ratio of telogen to tetrohydrofurane, or to tetrahydrofurane and the comonomer, is changed, b) then the mean molecular weight of at least one sample is determined, c) as long as the mean molecular weight determined in this way deviates from the molecular weight to be achieved by the change, the previously formed polytetrahydrofurane, or the tetrahydrofurane copolymers, the monoesters or diesters of the polytetrahydrofurane, or tetrahydrofurane copolymers, are at least partially depolymerized on an acid catalyst, and d) the tetrahydrofurane recaptured by means of depolymerization is returned at least partially to the polymerization process.
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