3.3- dimethylthietane polymerization initiation

Block copolymers of methylthiirane with thiirane or with 2,2-dimethylthiirane have also been obtained by sequential polymerizations initiated in the first phase by 2-naphthylsulfonylmethylene anions.Cationic polymerization has found use in the conversion of 3,3-dimethylthietane to SH-ended oligomers which could be coupled with hydroxyl-ended POE chains by reaction with a diisocyanate, but attempts to obtain block polymers of this thietane by direct initiation with cationic polystyrene were not successful. 

NMR studies of the polymerization of THF, oxepane, 3,3-dimethylthietane, 2-methoxy-2-oxo-l,3,2-dioxaphosphorinane and 2-methyl-2-oxazoline revealed that the structures of the growing qj ies are the corresponding onium ions these structures are given in Table 7 (earlier, the first reaction products, formed upon initiation, were observed in the polymerization of THF ). 

The polymerization of cyclic sulfides and amines provided, although tentatively, some information on kp and kp. The equality k kp was found (the Kq value measured for an initiator used was further applied in the determimtion of a in polymerization studies) in the polymerization of 3,3-dimethylthietane in CgHsNOa and qualitatively for l-phenylmethyl-2-methyl-aziridine Small differences were found between kp and k (the macrocation being less... 

The application of 300 MHz H-NMR to the polymerization of 3,3-dimethylthietane initiated with trialkyloxonium tetrafluoroborate (initiator concentration higher than 0.02 mole 1 ) permits polymeric sulfonium ions to be observed ... 

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