Methacrylic block copolymers by sulfur free RAFT (SF RAFT) free radical emulsion polymerisation

Abstract

A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. We demonstrate the use of sulfur free reversible addition-fragmentation chain transfer polymerisation (RAFT as a versatile tool for the controlled synthesis of methacrylic block and comb-like copolymers. Sulfur free RAFT (SF-RAFT) utilises vinyl terminated macromonomers obtained via catalytic chain transfer polymerisation (CCTP) of methacrylates as a chain transfer agent (CTA), and thus precluding adverse aspects of the RAFT such as toxicity of dithioesters. We have synthesised a range of narrow dispersity block copolymers (Đ < 1.2) and comb-like macromolecules by employing emulsion polymerisation allowing for the preparation of relatively large quantities (~50 g) of the above mentioned copolymers promptly and straightforwardly. Copolymers were characterised using 1 H NMR, size exclusion chromatography (SEC), thermogravimetric analysis (TGA) and matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-TOF-MS) techniques.

Cu(0)-RDRP of styrene: balancing initiator efficiency and dispersity

“…The development of reversible addition fragmentation chain-transfer (RAFT) [1][2][3] polymerisation, nitroxide mediated polymerisation (NMP) [4][5][6] and atom transfer radical polymerisation (ATRP) [7][8][9][10][11] have allowed the synthesis of complex polymeric materials with controlled architecture and molecular weight, narrow molecular weight distributions and high end group functionality. [12][13][14][15][16][17][18][19][20] Among these techniques, Cu(0)-wire RDRP 21 (single electron transfer living radical polymerisation (SET LRP) 22 or supplemental activator and reducing agent (SARA) ATRP) 23 has attracted considerable attention as a versatile and robust methodology demonstrating broad monomer scope, yielding polymers with high end group fidelity even at near-quantitative conversions. 24,25 Perhaps the most significant advantage of Cu(0)-RDRP is its simplicity 26 as the reactions can often be carried out in a disposable vial (rather than Schlenk tubes) with simple deoxygenation via nitrogen bubbling for a few minutes being sufficient for a controlled polymerisation, rather than time-consuming freeze-pump-thaw cycles.…”

In situ stabilizer formation from methacrylic acid macromonomers in emulsion polymerization

“…The macromonomers will react via an addition-fragmentation chain transfer mechanism with methacrylates and the process will result in surface-active block copolymers. In fact it is exactly this mechanism (in combination with low monomer concentrations) that has recently been coined "sulfur-free RAFT" by Haddleton and coworkers, 23,24 and was recently used by Zetterlund and coworkers 25 in a "non-living version" of polymerization induced self-assembly (PISA). 26 With acrylates the macromonomers will ultimately yield graft copolymers.…”

Sequence-definition from controlled polymerization: the next generation of materials

“…Further optimization of this approach resulted in the synthesis of comb-like diblock polymers and the scope was expanded by using four different macro chain transfer agents. 57,58 Other one-pot synthesis approaches focus on the use of hydrophobic/hydrophilic monomers or exploit the donor/acceptor interaction of styrene/Nsubstituted maleimides to synthesize new types of SC polymers. [59][60][61] Ji et al adapted the principle by using furan protected maleimides.…”