Jump to main content
Jump to site search

Issue 37, 2019
Previous Article Next Article

Ab initio RAFT emulsion polymerization mediated by small cationic RAFT agents to form polymers with low molar mass dispersity

Author affiliations

Abstract

We report on low molar mass cationic RAFT agents that provide predictable molar mass and low molar mass dispersities (Đm) in ab initio emulsion polymerization. Thus RAFT emulsion polymerization of styrene in the presence of the protonated RAFT agent, ((((cyanomethyl)thio)carbonothioyl)(methyl)amino)pyridin-1-ium toluenesulfonate (4), and the analogous methyl-quaternized RAFT agents, 4-((((cyanomethyl)thio)carbonothioyl)(methyl)amino)-1-methylpyridin-1-ium dodecyl sulfate (6), provide low dispersity polystyrene with Đm 1.2–1.4 for Mn ∼ 20 000. We postulate that the success of ab initio emulsion polymerization with 4 is due to the hydrophilicity of the pyridinium group, which is such that the water soluble RAFT agent partitions predominantly into the aqueous phase under the conditions of the experiment and that 4 provides little retardation. With 6, when the counterion is dodecyl sulfate, we can achieve “surfactant-free” RAFT emulsion polymerization to provide a low Đm polystyrene. However, the RAFT end-group is lost on isolation of the polymer. Preliminary results show that this class of RAFT agent is broadly applicable in ab initio emulsion polymerization of other more-activated monomers (e.g., butyl acrylate, butyl methacrylate). Furthermore, cyanomethyl(pyridin-4-yl)carbamodithioate (3, the RAFT agent in neutral form) provides molar mass control and Đm < 1.8 in ab initio emulsion polymerization of less activated monomers, specifically, the vinyl esters, vinyl acetate and vinyl benzoate.

Graphical abstract: Ab initio RAFT emulsion polymerization mediated by small cationic RAFT agents to form polymers with low molar mass dispersity

Back to tab navigation

Supplementary files

Article information


Submitted
19 Jun 2019
Accepted
25 Jul 2019
First published
29 Jul 2019

Polym. Chem., 2019,10, 5044-5051
Article type
Paper

Ab initio RAFT emulsion polymerization mediated by small cationic RAFT agents to form polymers with low molar mass dispersity

S. J. Stace, J. Vanderspikken, S. C. Howard, G. Li, B. W. Muir, C. M. Fellows, D. J. Keddie and G. Moad, Polym. Chem., 2019, 10, 5044
DOI: 10.1039/C9PY00893D

Social activity

Search articles by author

Spotlight

Advertisements