Macrocyclic polystyrenes were prepared by coupling a two-ended living precursor dianions with 1,3-bis(1-phenylethylenyl)benzene (DDPE). Experiments were performed in a drybox apparatus, and macrocycles were obtained with a yield ranged between 40 and 55%. Simultaneously, besides the expected cyclic polymer, polycondensates (linear and cyclic) were formed. Thus, macrocyclic products were separated from the residual linear precursor and linear polycondensates byproducts by preparative high performance liquid chromatography at the exclusion−adsorption transition point. Isolation of highly pure cyclic polystyrenes (of different sizes) was carried out. Information on the chemical structure of the linear and cyclic polystyrenes were obtained by matrix-assisted laser desorption/ionization time-of-flight (MALDI−TOF) mass spectrometry, showing a good agreement with the expected structures. In addition, viscometry measurements by SEC (viscometry detector) showed that the ratio g‘ = [η]C/[η]L is equal to 0.67 in a good solvent and confirmed the high efficiency of the preparative liquid chromatographic separation.

Multisegmented degradable polymers were successfully synthesized via atom transfer radical cross-coupling of α,ω-dihalogenated polymers prepared by atom transfer radical polymerization with dinitroxides. High molecular weight polymers (M n > 100 000 g mol-1) with more than 10 cleavable units in the main chain were prepared. These multisegmented polymers were chemically and thermally degraded. Chemical degradation, via basic hydrolysis or disulfide reduction, as well as thermal degradation, by heating in the presence or in the absence of free nitroxides, led to low molecular weight polymers with relatively low polydispersity (2100 g mol-1 ≤ M n ≤ 15 100 g mol-1; 1.08 ≤ M w/M n ≤ 1.46).