TY  - THES
A1  - Möller, Eléonore
T1  - Copolymerizations of vinylidene fluoride and hexafluoropropene in supercritical carbon dioxide (scCO2)
Y1  - 2010
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Siegmann, Rebekka
A1  - Möller, Eleonore
A1  - Beuermann, Sabine
T1  - Propagation rate coefficients for homogeneous phase VDF-HFP copolymerization in supercritical CO2
JF  - Macromolecular rapid communications
N2  - For the first time, propagation rate coefficients, kp,COPO, for the copolymerizations of vinylidene fluoride and hexafluoropropene have been determined. The kinetic data was determined via pulsed-laser polymerization in conjunction with polymer analysis via size-exclusion chromatography, the PLP-SEC technique. The experiments were carried out in homogeneous phase with supercritical CO2 as solvent for temperatures ranging from 45 to 90 degrees C. Absolute polymer molecular weights were calculated on the basis of experimentally determined MarkHouwink constants. The Arrhenius parameters of kp,COPO vary significantly compared with ethene, which is explained by the high electronegativity of fluorine and less intra- and intermolecular interactions between the partially fluorinated macroradicals.
KW  - copolymerization
KW  - fluorinated olefins
KW  - kinetics (polym)
KW  - pulse laser initiated polymerization
KW  - radical polymerization
Y1  - 2012
U6  - https://doi.org/10.1002/marc.201200115
SN  - 1022-1336
VL  - 33
IS  - 14
SP  - 1208
EP  - 1213
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Möller, Eleonore
A1  - Beuermann, Sabine
T1  - Homogeneous phase copolymerizations of vinylidene fluoride and hexafluoropropene in supercritical carbon dioxide
JF  - Macromolecular reaction engineering
N2  - Copolymerizations of vinylidene fluoride (VDF) and hexafluoropropene (HFP) were carried out in homogeneous phase with supercritical carbon dioxide up to complete VDF conversion using conventional peroxide initiators. The HFP monomer feed ratios, f(HFP), were varied between 0.65 and 0.20. Depending on f(HFP) amorphous or semi-crystalline copolymers were obtained. f(HFP) also determines the minimum pressure required to allow for homogeneous phase reactions. For example, HFP-rich copolymerizations in 70 wt.-% CO(2) at 100 degrees C require a pressure of around 500 bar. Further, bulk copolymerizations in homogenous phase were feasible for f(HFP) 0.65 at 900 bar up to complete VDF conversion. Copolymerizations in the presence of perfluorinated hexyl iodide carried out at 75 degrees C gave access to low dispersity polymers. Due to homogeneous phase conditions the use of any surfactants or fluorinated cosolvent is avoided.
KW  - copolymerization
KW  - hexafluoropropene
KW  - phase behavior
KW  - supercritical CO(2)
KW  - vinylidene fluoride
Y1  - 2011
U6  - https://doi.org/10.1002/mren.201000031
SN  - 1862-832X
VL  - 5
IS  - 1
SP  - 8
EP  - 21
PB  - Wiley-VCH
CY  - Weinheim
ER  -