Silicon-Based and Fluorinated Polymeric Surfactants for Nitroxide Mediated Dispersion Polymerization in Supercritical Carbon Dioxide
-
Ramirez-Wong, Diana Guadalupe; Posada-Velez, Carlos Andres; Saldivar-Guerra, Enrique; Luna-Barcenas, J. Gabriel; Ott, Christina; Schubert, Ulrich S.
- Abstract:
- Block copolymers based on siloxanes and fluorinated block copolymers
were synthesized and tested as surfactants for nitroxide mediated polymerizations
(NMP) in supercritical carbon dioxide. Styrene was polymerized in the presence of
TEMPO at 130 8C using various surfactants. Siloxane-based surfactants were synthesized
by a new route based on NMP; the perfluorinated surfactants were also
synthesized by NMP. The dispersion polymerizations of styrene in scCO2 reveal
conversions of up to 35% in 4 hours at 19.1 MPa. The resulting polydispersity indices
lie in the range 1.2–1.4. The best results are obtained using a perfluorinated surfactant.
Preliminary copolymerization experiments of the polystyrene macroinitiator in scCO2
have shown successful chain-extension with butyl acrylate (BuA) resulting in the
formation of a poly (St-b-BuA) block copolymer.
- Year:
- 2009
- Type of Publication:
- Article
- Journal:
- Macromolecular Symposia
- Volume:
- 283 - 284
- Pages:
- 120 - 129