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  - Vukicevic, Radovan
A1  - Vukovic, Ivana
A1  - Stoyanov, Hristiyan
A1  - Korwitz, Andreas
A1  - Pospiech, Doris
A1  - Kofod, Guggi
A1  - Loos, Katja
A1  - ten Brinke, Gerrit
A1  - Beuermann, Sabine
T1  - Poly(vinylidene fluoride)-functionalized single-walled carbon nanotubes for the preparation of composites with improved conductivity
JF  - Polymer Chemistry
N2  - The surface of single-walled carbon nanotubes (SWCNTs) was functionalized with azide-terminated poly(vinylidene fluoride) (PVDF). Functionalization was confirmed by dispersibility, Raman spectroscopy, and thermogravimetric analyses. Raman spectra show disordering of the SWCNTs, thus, strongly suggesting that PVDF was covalently attached to SWCNTs. Functionalized SWCNTs were mixed with commercially available PVDF in a twin-screw extruder and thin films were obtained by melt-pressing. Films containing 0.5 and 1 wt% PVDF-functionalized SWCNTs exhibited significantly improved electrical conductivity compared to PVDF films containing pristine SWCNTs.
Y1  - 2012
U6  - https://doi.org/10.1039/c2py20166f
SN  - 1759-9954
VL  - 3
IS  - 8
SP  - 2261
EP  - 2265
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Barth, Johannes
A1  - Siegmann, Rebekka
A1  - Beuermann, Sabine
A1  - Russell, Gregory T.
A1  - Buback, Michael
T1  - Investigations into chain-length-dependent termination in bulk radical polymerization of 1H, 1H, 2H, 2H-Tridecafluorooctyl methacrylate
JF  - Macromolecular chemistry and physics
N2  - The SP-PLP-EPR technique is used to carry out a detailed investigation of the radical termination kinetics of 1H, 1H, 2H, 2H-tridecafluorooctyl methacrylate (TDFOMA) in bulk at relatively low conversion. Composite-model behavior for chain-length-dependent termination rate coefficients, kti,i, is observed. It is found that for TDFOMA, ic approximate to 60 independent of temperature, and as approximate to 0.65 and al approximate to 0.2 at 80 degrees C and above. However, at lower temperatures the situation is strikingly different, with the significantly higher average values of as = 0.89 +/- 0.15 and al = 0.32 +/- 0.10 being obtained at 50 degrees C and below. This makes TDFOMA the first monomer to be found that exhibits clearly different exponent values, as and al, at lower and higher temperature, and that has both a high as, like an acrylate, and a high ic, like a methacrylate.
KW  - ESR
KW  - EPR
KW  - kinetics (polym
KW  - )
KW  - methacrylates
KW  - radical polymerization
KW  - termination
Y1  - 2012
U6  - https://doi.org/10.1002/macp.201100479
SN  - 1022-1352
VL  - 213
IS  - 1
SP  - 19
EP  - 28
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - Vukicevic, Radovan
A1  - Schwadtke, Ulrike
A1  - Schmuecker, Simon
A1  - Schaefer, Philipp
A1  - Kuckling, Dirk
A1  - Beuermann, Sabine
T1  - Alkyne-azide coupling of tailored poly(vinylidene fluoride) and polystyrene for the synthesis of block copolymers
JF  - Polymer Chemistry
N2  - The synthesis of block copolymers consisting of poly(vinylidene fluoride) (PVDF) and polystyrene (PS) is reported. Firstly, a propargyl-functionalized alkoxyamine initiator (PgOTIPNO) was prepared and subsequently used for the preparation of a propargyl-terminated PS homopolymer of different chain lengths with low dispersities via nitroxide-mediated radical polymerization. A tailored PVDF homopolymer with iodine end groups originating from iodine transfer polymerization was transformed to PVDF with azide end group. Then, alkyne-terminated PS with different molecular weights and azide-terminated PVDF were joined together via copper-catalyzed alkyne-azide coupling. The block copolymers were characterized using H-1-NMR, F-19-NMR, IR, SEC, and DSC.
Y1  - 2012
U6  - https://doi.org/10.1039/c1py00427a
SN  - 1759-9954
VL  - 3
IS  - 2
SP  - 409
EP  - 414
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -