Preparation and Analysis of Bicyclic Polystyrene

Abstract

Bicyclic polystyrene was prepared by combining atom transfer radical polymerization and click chemistry. The bicyclic polymer was separated from concurrently produced acyclic (branched) polymers through fractional precipitation, and its purity was quantified by two-dimensional liquid chromatography analysis. The structure of bicyclic polymer was characterized by SEC, MALDI–TOF MS, 1H NMR, and FT-IR.

Covalent fixed multicyclic polystyrene conformers

“…The click reaction between the PS having insufficient azide end group and coupling agent could produce the cyclic branched product bearing reactive acetylene groups. These remaining acetylene groups react with other azide‐terminated star polymer to form a branched high molecular weight byproduct . The purities of Mcyc‐PSs were identified by Gaussian multiple peak fitting and subsequent peak integration and confirmed to be 64.9% and 50.7% in 8a and 8b , respectively (Fig.…”

“…In addition, the nanostructures of the cyclic polymers exhibited higher stability in solution because their assemblies are formed densely . Cyclic polymers have been synthesized with various structures such as theta‐, tadpole‐, eight‐, and manacle‐ topologies by combination of various polymerization methods including controlled radical polymerization, ring opening polymerization, anionic polymerization with coupling chemistry such as electrostatic self‐assembly and covalent fixation and “click” reaction.…”

“…Click coupling between azide‐terminated star polymer precursors and multifunctional alkyne coupling agents was employed successfully to synthesize theta‐shaped, 8‐shaped bicyclic polymer and also, cage‐shaped tricyclic polymer . Recently, we reported that the T g of multicyclic polymers was higher than that of 4‐arm star polymer precursors; especially, the cage‐shaped tricyclic polymer with severe topological constraint showed the highest T g among them …”

Improved synthesis of bicyclic polystyrenes by ATRP and “click” reaction

“…The retention time of bicyclic polystyrene (26.1 min) increased in comparison with 3 (25.4 min) due to its compact hydrodynamic volume, resulted from the cyclization. The appearance of broad multimodal peaks on SEC trace after click reaction indicated high-molecular-weight byproducts such as dimeric or trimeric branched polystyrenes (6) resulted from intermolecular reaction between intermediate species and individual reactants [11]. The purity of bicyclic polystyrene was obtained from SEC traces by Gaussian multiple peak fitting and subsequent peak integration (Fig.…”

“…Recently, our group prepared bicyclic polystyrenes by the combination of ATRP and click coupling reaction [11]. Highmolecular-weight impurities were observed during click coupling reaction of bicyclic polystyrenes.…”