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The synthesis of macrocyclic polystyrene‐ block‐poly(2‐vinylpyridine) and macrocyclic polystyrene‐ block‐poly(dimethylsiloxane) was carried out by initiation of 2‐vinylpyridine (2VP) and hexamethyl‐cyclotrisiloxane (D3) by difunctional living polystyryllithium followed by coupling with 1,4‐bis(bromethyl)benzene (1,4‐DBX) and dichloro‐dimethylsilane (Cl2SiMe2), respectively. A small portion of the living ABA precursors were protonated to serve as isobaric linear precursors. The linear and macrocyclic block copolymers were characterized by size‐exclusion chromatography (SEC). The ratios of apparent cyclic/linear SEC molecular‐weight maxima versus degree of polymerization (DP) show increases with decreasing DP varying from 0.70 ± 0.03 at high DP ≤ 200 to 0.78 ± 0.044 at low DP (≥60) whereas that of the linear ABA block copolymers decreased. Increases in glass transition temperature (Tg) were also observed for the cyclic PS‐b‐PDMS copolymers with respect to the isobaric linear precursors. The macrocycles were characterized by 1H and 13C NMR and in the case of macrocyclic PS‐b‐PDMS by 29Si NMR as well. Broadening in the NMR absorptions of the macrocyclic block copolymers is general and is similar to that observed for the homopolymers. Differemtial scanning calorimetry (DSC) analysis of the PS‐b‐P2VP macrocycles shows increases in Tg at lower molecular weight as was observed for the PS and P2VP macrocycles.

The synthesis, isolation, and characterization are reported of a polystyrene−poly(2-vinylpyridine) block copolymer “catenane” with a molecular weight of about 10 000 and containing about equal masses of each of the rings. This catenane is prepared by end-to-end coupling of a P2VP dianion lithium salt with 1,4-bis(bromomethylbenzene) in THF in the presence of a PS macrocycle (M p = 4500). The catenane was isolated by precipitation−extraction procedures that were optimized using a 50/50 PS-b-P2VP macrocycle as a model for the catenane. The catenane copolymer was characterized by SEC, 1H NMR, and emission (fluorescence) spectroscopy.

The anionic polymerizations of trimethylvinylsilane (TMVS) initiated by t-BuLi in toluene at −20 °C and of phenyldimethylvinylsilane (PDMVS) at 0−20 °C proceed in high yields (>95%), giving narrow molecular weight distribution (MWD ≤ 1.15) polymers. Polystyrene−PTMVS AB block copolymers having relatively narrow molecular weight distributions were synthesized by initiation of TMVS by poly(styryllithium). The reaction of poly(phenyldimethylvinylsilane) (PPDMVS) with HBF4·Et2O in toluene at 60 °C resulted in the formation of poly(fluorodimethylvinylsilane) (PFDMVS) as shown by 1H and 19F NMR.