Unexpected reactivity for the RAFT copolymerization of oligo(ethylene glycol) methacrylates

Abstract

Homo‐ and copolymers of di(ethylene glycol) methyl ether methacrylate (DEGMA) and oligo(ethyleneglycol) methyl ether methacrylate (OEGMA1100) were synthesized with various chain lengths via reversible addition fragmentation chain transfer (RAFT) polymerization in ethanol using [M]/[RAFT] ratios of 100 and 200. Kinetic investigations on the homo‐ and copolymerization of these monomers were performed using a parallel synthesizer resulting in well‐defined polymers with polydispersity indices mostly below 1.3. The polymerization kinetics are presented and discussed in detail surprisingly revealing that the DEGMA homopolymerization is slower than the OEGMA1100 homopolymerization. Transfer coefficients c were estimated to be ∼0.5 for the RAFT polymerization of both DEGMA and OEGMA1100 resulting in hybrid behavior at the beginning of the polymerizations. Subsequent copolymerization also revealed fast incorporation of the OEGMA1100 and relatively slow incorporation of DEGMA resulting in well‐defined copolymers with a molecular weight up to 100 kDa and polydispersities around 1.20. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2811–2820, 2009

Tuning thermoresponsive behavior of diblock copolymers and their gold core hybrids

“…This has also been reported by other groups [58], particularly when the DEGMA block is polymerized after the OEGA block (Table 2), and is attributed to greater steric hindrance [25,[49][50][51]53,59] around the active radical center (macro-CTA) from the OEGA. Nevertheless, the correlation between initial OEGA monomer feed (f O ) and OEGA composition in the copolymer (F O ) is high (Fig.…”

High‐Throughput Method for RAFT Kinetic Investigations and Estimation of Reactivity Ratios in Copolymerization Systems

“…RAFT is one of the most straightforward controlled polymerization techniques, requiring no additional skills or precautions beyond those required to carry out a conventional radical polymerization. Additionally, as demonstrated here and elsewhere,2, 3, 6, 8, 11, 14, 18 it is amenable to use with techniques of high‐throughput synthesis. It is expected that the application of high throughput techniques and RAFT technology to the preparation of gradient copolymers1, 23 will allow the rapid generation of libraries of materials, facilitating the evaluation of the properties of this interesting class of materials.…”

“…This high‐throughput methodology was successfully tested in terms of precision and accuracy for reversible addition‐fragmentation chain transfer (RAFT) polymerization reactions 2, 3, 6. Next to other high‐throughput polymerization methodologies developed for commercially available parallel synthesizers7–13–which have allowed unattended and rapid kinetic investigations2, 3, 13–16 and the synthesis of functional polymers,7, 9, 17 and random13, 18 and block 10, 12, 19, 20. copolymer libraries–, the recently reported automated parallel freeze‐evacuate‐thaw degassing technique,6 which has been successfully implemented for polymerization reactions controlled by switchable dithiocarbamate RAFT agents,2, 3 expands the portfolio of high‐throughput experimental methodologies available for polymer synthesis.…”

pH- and temperature-responsive amphiphilic diblock copolymers of 4-vinylpyridine and oligoethyleneglycol methacrylate synthesized by RAFT polymerization

“…1 are considered together. This phenomenon was explained by Pietsch et al as a hybrid behavior [27] that free radical and RAFT polymerizations proceed together during RAFT pre-equilibrium. Short inhibition time observed in the beginning of polymerizations is caused by the rate retardation effect in dithiobenzoate mediated polymerizations [28].…”