RAFT-Mediated Emulsion Polymerization of Styrene in Water using a Reactive Polymer Nanoreactor

Carl N. Urbani; Michael J. Monteiro

doi:10.1071/CH09222

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RAFT-Mediated Emulsion Polymerization of Styrene in Water using a Reactive Polymer Nanoreactor

Carl N. Urbani ^A and Michael J. Monteiro ^A ^B

+ Author Affiliations

- Author Affiliations

^A Australian Institute of Bioengineering and Nanotechnology, University of Queensland, St Lucia, Brisbane, Qld 4072, Australia.

^B Corresponding author. Email: m.monteiro@uq.edu.au

Australian Journal of Chemistry 62(11) 1528-1532 https://doi.org/10.1071/CH09222
Published: 20 November 2009

Abstract

We have demonstrated a nanoreactor methodology to produce polystyrene nanoparticles with narrow molecular weight distributions (MWD) and control over the final particle size distributions. Our reactive thermoresponsive diblock copolymer nanoreactor is an ideal setting to carry out otherwise difficult reversible addition–fragmentation chain transfer (RAFT)-mediated polymerizations, resulting in surfactant-free nanoparticles that can be tuned to size and MWD. By confining the MacroRAFT agent within the nanoreactor, the poor P(DMA₆₈-b-NIPAM₇₃)-SC(=S)SC₄H₉ (PNIPAM) leaving group on the MacroCTA behaves as a highly active MacroCTA through kinetic rather than thermodynamic control. The M_n was close to theory with low polydispersity indices (PDIs) (<1.2). The particle size increased with the ratio of styrene to nanoreactors and with very narrow particle size distributions. However, we found that there was a limited amount of styrene monomer that can be encapsulated into the nanoreactor, leading to polymerizations stopping well before full conversion. This problem was overcome through the addition of a non-reactive thermoresponsive diblock copolymer, which resulted in M_ns close to 340 K and low PDIs.

Manuscript received: 15 April 2009.

Manuscript accepted: 15 July 2009.

Acknowledgements

The authors wish to dedicate this paper to Dr Ezio Rizzardo (CSIRO, Australia) for pioneering this area and allowing us to enjoy the benefits that RAFT has brought to our science and the building of friendships within the RAFT scientific community. M.J.M. acknowledges financial support from the ARC Discovery grant (DP0987315).

References

RAFT-Mediated Emulsion Polymerization of Styrene in Water using a Reactive Polymer Nanoreactor

Abstract

Acknowledgements

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