Telechelic tetrahydrofuran

Abstract

AbstractCondensation polymers with block structure are stable only if one of the constituent blocks is stable against reactions like transesterification, transamidation, etc. This stable block must have a pure CC chain which may be interrupted by ether, sulfide or sulfone linkages. It must be strictly bifunctional in order to be no limiting factor for the molecular weight in the synthesis of blockcopolymers.If the two functional groups are located at both ends of the polymer chain, we name this product a telechelic. The characterization of telechelics needs the determination of the functionality. Any end group analysis will give only average values. An efficient chromatographic method is necessary to guarantee that bifunctionality is caused by one polymer homologous series.A number of commercial telechelic polytetrahydrofuranes are strictly bifunctional as shown by GPC1). Two functional end groups can be introduced either by bifunctional initiation and killing the living end groups by a proper nucleophile. The disadvantage of this method is that one mole of an expensive initiator is needed to produce one mole of polymer. The second method to introduce functional end groups uses a proper transfer agent. Only catalytic amounts of initiator are necessary in this case.