The effect of Z-group modification on the RAFT polymerization of N-vinylpyrrolidone controlled by “switchable” N-pyridyl-functional dithiocarbamates

Abstract

ARTICLE This journal isThe ability of a RAFT agent to control the polymerization of a monomer is dictated by the structures of both the monomer and the RAFT agent. In this paper, the polymerization of Nvinylpyrrolidone was examined with a series of cyanomethyl N-aryl-N-pyridyl dithiocarbamates [(4-RʹPh)N(py)C(=S)SCH 2 CN] varying in the substituent (Rʹ) at the 4position on the phenyl ring. The polymerization of N-vinylpyrrolidone was best controlled when Rʹ was methoxy; one of the least active RAFT agents in the series. The preservation of RAFT agent functionality was demonstrated by chain extension experiments with further Nvinylpyrrolidone. Again best control again was found for the RAFT agent with Rʹ=MeOPh. The utility of this RAFT agent was also proved with the preparation of poly( Nisopropylacrylamide)-block-poly(N-vinylpyrrolidone).

4-Halogeno-3,5-dimethyl-1H-pyrazole-1-carbodithioates: versatile reversible addition fragmentation chain transfer agents with broad applicability

“…It is also possible to switch the activity of certain dithiocarbamates to provide good control over both MAMs and LAMs. These RAFT agents enabled the preparation of low‐dispersity (low‐ Đ ) poly(MAM)‐ block ‐poly(LAM)s by sequential monomer addition . A few dithiocarbamates (those with ‘ZC(S)S’ as shown in the centre of Fig.…”

Effect of the Z‐ and Macro‐R‐Group on the Thermal Desulfurization of Polymers Synthesized with Acid/Base “Switchable” Dithiocarbamate RAFT Agents

“…For MMA polymerization (a 1,1‐disbsituted monomer), it was necessary to use 2‐cyanopropan‐2‐yl N ‐methyl‐ N ‐(pyridin‐4‐yl)carbamodithioate 2 as RAFT agent. The polymerization conditions are based on previous work: St, NIPAm, MMA, VAc, and NVP (see Table S1, Supporting Information). For poly(LAM), the RAFT agent was used in its unswitched (neutral) form.…”

“…A prime example are acid/base switchable N ‐pyridyl‐functional dithiocarbamate RAFT agents, which provide the ability to control the polymerization of both more activated monomers (MAMs) and less activated monomers (LAMs). By switching the RAFT agent Z‐group between a neutral pyridyl (e.g., in 1 or 2 ) and a charged pyridinium moiety, (e.g., in 1 ‐H + or 2 ‐H + ) low dispersity block copolymers comprising both MAMs and LAMs can be prepared.…”

“…In our previous investigations, [10,[12][13][14]16] the N-pyridylfunctional dithiocarbamate RAFT agents and their derived polymers were found to be unusually robust. For example, their high hydrolytic stability allows aqueous polymerization in strongly acidic solution (e.g., pH ≤ 2) with no discernible loss of end group functionality.…”

Reversible addition-fragmentation chain transfer (co)polymerization of conjugated diene monomers: butadiene, isoprene and chloroprene

“…The most used RAFT agents for conjugated diene monomers are trithiocarbonates ( 18–29 ) or 2‐phenylethanedithioates ( 16 , 17 ). Other RAFT agents of similar activity, for example the 3,5‐dimethyl‐1 H ‐pyrazole‐1‐carbodithioates, and the switched form of switchable RAFT agents are also likely to be successful in providing good control and low dispersities. Dithiobenzoates (e.g.…”