Homophase and heterophase polymerizations of butyl acrylate mediated by poly(acrylic acid) as a reversible addition–fragmentation chain-transfer agent

Emulsifier‐free reversible addition–fragmentation chain transfer emulsion polymerization of alkyl acrylates mediated by symmetrical trithiocarbonates based on poly(acrylic acid)

“…However, according to our previous data, the insertion of several units of alkyl acrylate into the PAA chain results in enhancing the surface active properties of the polymer . After reaching the critical micelle concentration, which is typically below 0.1 wt% (it corresponds to ca 1% conversion of polymeric RAFT agent), the amphiphilic block copolymers form micelles.…”

“…As mentioned above, the typical feature of acrylate emulsion homopolymerization and copolymerization in the presence of a hydrophilic or amphiphilic macroRAFT agent based on symmetric trithiocarbonate is a bimodal MWD of the products. At the same time, unlike ab initio emulsion polymerization, both dispersion and solution polymerizations of BA mediated by PAATC resulted in unimodal MWD . We suppose that the low molecular weight fraction corresponds to the block copolymer with a short hydrophobic block formed during stage I of the emulsion batch polymerization, while the high molecular weight mode can be attributed to further grown polymer.…”

“…Evidently, the slow consumption of the oligomeric block copolymer cannot be explained by its low efficiency in polymerization from a chemical standpoint. First, it exhibits high efficiency in dispersion and solution polymerizations . Moreover, in the structure of the intermediate radical which is formed after addition of the propagating radical to the C=S bond of the block copolymer with the trithiocarbonate group, the chemical nature of all the monomer units attached to sulfur atoms of the trithiocarbonate group of the intermediate product is the same.…”

“…symmetrical trithiocarbonates that enable the synthesis of ABA triblock copolymers, have attracted much less attention. In our previous studies of emulsion homopolymerization and copolymerization of n ‐butyl acrylate (BA) in the presence of poly(acrylic acid) (PAA) based macroRAFT agents containing the trithiocarbonate group within the chain, we have analyzed the influence of monomer(s) to the medium volume ratio, the polymerization degree and the chemical nature of the co‐monomer in the macroRAFT agent on polymerization kinetics, particle size and morphology, and the molecular weight distribution (MWD) of the polymerization products …”

“…In contrast, emulsifier‐free emulsion polymerization of acrylates mediated by the same macroRAFT agents A–S–C(=S)–S–A, based on for example PAA trithiocarbonate, leads to different results . In contrast to products of solution or dispersion polymerization, the products of emulsion polymerization are typically characterized by a bimodal MWD in a wide range of monomer conversion.…”