One-Pot Hyperbranched Polymer Synthesis Mediated by Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerization

Abstract

Reversible addition fragmentation chain transfer (RAFT) polymerization was used for the first time to produce poly(methyl methacrylate) hyperbranched polymers via the one-pot copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate, mediated by 2-(2-cyanopropyl) dithiobenzoate. Hyperbranched structures were characterized by 1H NMR spectroscopy, size exclusion chromatography (SEC), and thermal analyses. Monomer conversions and molecular weight distributions of hyperbranched poly(methyl methacrylate) (PMMA) prepared via RAFT polymerization are much higher and much lower, respectively, than those of the analogous polymers prepared via other living polymerization systems. Furthermore, the living character of the RAFT process was used to polymerize styrene from hyperbranched PMMA precursors (macro chain-transfer agent, macroCTA) and to produce starlike structures with hyperbranched PMMA as the core and polystyrene as the arms. DSC and SEC analyses support the observations made regarding the production of these novel architectures.

Tuning the Solubility of Copper Complex in Atom Transfer Radical Self-Condensing Vinyl Polymerizations to Control Polymer Topology via One-Pot to the Synthesis of Hyperbranched Core Star Polymers

“…Sherrington et al investigated the effect of adding large amounts of thiol-based chain transfer agents to avoid gelation to obtain branched methacrylic copolymers [43]. The specific concept of "active site transfer" has also been investigated in the RAFT polymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) [44]; anionic SCVP of divinylbenzene (DVB) and 1,3-isopropenylenebenzene [45]; AT-SCVP of DVB and (1-bromoethyl)benzene [46]; AT-SCVP of EGDMA and bisphenol A dimethacrylate [47]; and deactivation-enhanced AT-SCVP of commercially available multifunctional vinyl monomers [48]. A remarkable approach using Pd(II) and Ni(II) catalysts and very bulky chelating diimine ligands [49][50][51], has been reported for the formation of hyperbranched polyethylene at low pressure (a so-called "chain walking" process).…”

Facile one-spot synthesis of highly branched polycaprolactone

“…solventless), controlled ROP mechanism. [3][4][9][10][11][12][31][32][33][34][35][36][37][38][39][40] The 'Strathclyde Method' was a pivotal early example of such a branching synthetic strategy and centred on the standard free radical (SFR) copolymerisation of monofunctional and difunctional vinyl monomers. [9][10][11][12] One of the main conclusions drawn from this work was that gelation, i.e.…”

“…[3][4][31][32][33][34][35][36][37][38][39][40] To further probe this effect, this report focussed on investigating the impact that controlled characteristics has upon the outcome of the Strathclyde strategy for the synthesis of highly branched PCL when applied to bulk conditions.…”

Synthesis and characterisation of end-functionalised poly(N-vinylpyrrolidone) additives by reversible addition–fragmentation transfer polymerisation

“…Reversible addition-fragmentation chain transfer (RAFT) polymerization is a controlled radical polymerization technique of significant and topical interest and has been used successfully to produce a vast range of controlled polymeric structures including block copolymers [1][2][3][4] , branched polymers [4][5][6][7] and end-functionalized polymers [8][9][10] . All aspects of the RAFT polymerization mechanism including additional examples of the above described structures are reported in "The Handbook of RAFT Polymerization" by Barner-Kowollik 11 .…”