A kinetic study of the formation of polystyrene stars using 1,2-bis(trichlorosilyl)ethane

Linking Reaction Kinetics of Star Shaped Polystyrene by Temperature Gradient Interaction Chromatography

“…〈 M LS 〉 finally reaches the weight average molecular weight of the six-arm star, about 470 000 after the reaction for a few weeks while 〈 M CAL 〉 reaches an asymptotic value at 380 000. This result is in good qualitative agreement with the results of Frater et al…”

“…〈M LS 〉 finally reaches the weight average molecular weight of the six-arm star, about 470 000 after the reaction for a few weeks while 〈M CAL 〉 reaches an asymptotic value at 380 000. This result is in good qualitative agreement with the results of Frater et al 15 TGIC chromatogram of Star PS. In Figure 2 the TGIC chromatograms of the same set of star PS as of the SEC chromatograms shown in Figure 1 are displayed.…”

Synthesis and Isomeric Characterization of Well-Defined 8-Shaped Polystyrene Using Anionic Polymerization, Silicon Chloride Linking Chemistry, and Metathesis Ring Closure

“…However, a mixture of 2-arm star, 3-arm star, and 4-arm star was obtained; even after several fractionations it was not possible to obtain a pure 4-arm star. Therefore, a more efficient linking agent, 1,2-bis­(methyl­dichlorosilyl)­ethane, was chosen for further study because the ethylene spacer between the two silicon groups reduces steric crowding in the linking reaction with poly­(styryl)lithium arms; ,− in addition, the presence of protons in the ethylene bridge was found to facilitate the characterization of both the 4- star -polystyrene precursor and 8-shaped polystyrene using 1 H NMR.…”

Strategies for the Synthesis of Well-Defined Star Polymers by Anionic Polymerization with Chlorosilane Coupling and Preservation of the Star Architecture during Catalytic Hydrogenation

“…In hydrocarbon solvents the reaction between carbanions and chlorosilane coupling agents can take days or even weeks to go to completion; the reaction slows down precipitously as the number of arms increases due to increased steric hindrance. − Such lengthy reaction times necessitate the rigorous exclusion of impurities to levels achievable only by glassblowing techniques, but these difficult and time-consuming experimental procedures might be avoided if the time required to achieve complete coupling could be significantly reduced. It has been known for some time that the propagation rate of anionic polymerization increases sharply with the addition of polar additives, such as amines and ethers.…”