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

Abstract

Abstract:In this paper, we propose a simple one-pot methodology for proceeding from atom transfer reaction-induced conventional free radical polymerization (AT-FRP) to atom transfer self-condensing vinyl polymerization (AT-SCVP) through manipulation of the catalyst phase homogeneity (i.e., CuBr/2,2'-bipyridine (CuBr/Bpy)) in a mixture of styrene (St), 4-vinyl benzyl chloride (VBC), and ethyl 2-bromoisobutyrate. Tests of the solubilities of CuBr/Bpy and CuBr2/Bpy under various conditions revealed that both temperature and solvent polarity were factors affecting the solubility of these copper complexes. Accordingly, we obtained different polymer topologies when performing AT-SCVP in different single solvents. We investigated two different strategies to control the polymer topology in one-pot: varying temperature and varying solvent polarity. In both cases, different fractions of branching revealed the efficacy of varying the polymer topology. To diversify the functionality of the peripheral space, we performed chain extensions of the resulting hyperbranched poly(St-co-VBC) macroinitiator (name as: hbPSt MI) with either St or tBA (tert-butyl acrylate). The resulting hyperbranched core star polymer had high molecular weights (hbPSt-g-PSt: Mn = 25,000, Đ = 1.77; hbPSt-g-PtBA: Mn = 27,000, Đ = 1.98); hydrolysis of the tert-butyl groups of the later provided a hyperbranched core star polymer featuring hydrophilic poly(acrylic acid) segments. OPEN ACCESSPolymers 2014, 6 2553

Disulfide-Functionalized Unimolecular Micelles as Selective Redox-Responsive Nanocarriers

“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 favor the branching SCVP mechanism in relation to the formation of linear segments. 59 The overall inimer amount in the polymerizations was retained at 20 mol %, while the BBEMA/BSSMA feed ratio was varied to change the amount of disulfide in the backbone of the hyperbranched polymers ( Table 1). The inimer content was set to 20 mol % since it was hypothesized that this would result in a not to branched polymer structure, which would allow for enough space to facilitate guest molecule encapsulation.…”

Synthesis of Hyperbranched Polymers via Metal‐Free ATRP in Solution and Microemulsion

“…Among these highly branched polymers, hyperbranched polymers receive particular interest from both industries and academia because of their one‐pot inexpensive synthesis and retention of arborescent structures. Hyperbranched polymers typically could be produced in one pot via step‐growth polymerization of multifunctional AB m (m ≥ 2) monomers, [ 7–13 ] step‐growth copolymerization of A n and B m monomers (e.g., A 2 + B 3 ), [ 14–16 ] chain‐growth polymerization of AB m (m ≥ 2) monomers, [ 17–19 ] chain‐growth copolymerization of divinyl cross‐linkers, [ 20–26 ] self‐condensing vinyl polymerization (SCVP) of polymerizable initiators (inimers), [ 27–35 ] or polymerizable transfer agents (transmers). [ 36–40 ] It is important to note that any of these methods could produce hyperbranched polymers and randomly branched polymer as their difference lies in the fraction of branching unit incorporated into the polymer backbone.…”

Kinetic Model of the Amphiphilic Copolymers with Hyperbranched Core Formed by AB2Monomer and BfInitiator

“…Recently, many novel amphiphilic hyperbranched polymers have been prepared. The amphiphilic AB 2 star copolymer was synthesized by Liu et al Chen et al prepared a hyperbranched core star polymer with hyperbranched poly(St‐co‐VBC) macroinitiator in one‐pot methodology, in which the polymer topology was controlled by varying temperature and varying solvent polarity. The theoretical model is applicable for the core of AB g type polycondensation and self‐condensing vinyl polymerization.…”