Synthesis of well‐defined polychlorostyrenes by living radical polymerization with 4‐methoxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl

Abstract

Radical polymerization of 2-, 3-, and 4-chlorostyrenes (ClSts) was investigated with benzoyl peroxide (BPO) as an initiator, in the presence of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO). The polymerization was performed in bulk for 3.5 h at 95ЊC and then continued for a defined time at 125ЊC to give the corresponding poly(ClSt)s with narrow polydispersity in high yield. It was found that the polymerization proceeded in accordance with a living mechanism in all cases, because the molecular weight of the resulting polymers was proportional to the conversion, and inversely proportional to the initial concentration of MTEMPO. Furthermore, the polymers obtained from 2-and 3-ClSts quantitatively act as initiators for the polymerization in the living radical manner, of styrene to give the corresponding block copolymers, except for poly(4-ClSt). The thermal stability of the living poly(ClSt)s was found to decrease in the order of 2-ú 3-ú 4-ClSt on the basis of the results of their postpolymerizations.

Studies on controlled radical polymerisation using 5-membered cyclic PROXYL nitroxides and corresponding alkoxyamines

“…Electron-withdrawing styrene substituents were found to increase CRP rate in the presence of TEMPO [27] and 4-methoxy-TEMPO (MTEMPO). [28] Similarly, CRP of p-styrene sulfonate was found to occur at a much higher rate than styrene. [29] A study on CRP of methylstyrenes in the presence of MTEMPO indicated that polymerisation of the o-isomer was the most rapid due to steric hindrance.…”

“…The rate of TEMPO-mediated CRP of substituted styrenes was found to be greatest with monomers bearing electron-withdrawing substituents. [27][28][29] The phosphonato-substituted nitroxides reported by Tordo et al [12] are reported to give faster polymerisations than TEMPO due to the electron withdrawing influence of the phosphonate group. Presumably, the results in these cases are due to weakening of the alkoxyamine C1O bond by a negative inductive effect.…”

Synthesis of Poly(ε-caprolactone) with a Stable Nitroxyl Radical as an End-Functional Group and Its Application to a Counter Radical for Living Radical Polymerization

“…Whereas this polymer could be quantitatively obtained by the reaction of a living cationic PTHF and sodium 4-oxy-TEMPO, the TEMPO-supported PTHF acted as a polymeric counter radical for living radical polymerization of styrene, giving the poly(THF- block -styrene) in quantitative efficiency. The development of the method of this quantitative synthesis of the block copolymer has been based on numerous results, obtained by many investigators, concerning the styrene polymerization using TEMPO. − Our recent results can be included among this research. − In this recent study, it was found that the concentration of the growing polymer chain was identical to the initial concentration of TEMPO, with the result that all the polystyrenes obtained had the aminoxy moiety at their terminals …”

Living Free-Radical Polymerization—a Review

“…Styrene is the most studied monomer in NMLFRP (29,57,(64)(65)(66)(67)(68)(69)(70)(71)(72)(73)(74). The kinetics and mechanism of this process have been disclosed by Veregin et al (64).…”