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  - Herfurth, Christoph
A1  - Voll, Dominik
A1  - Buller, Jens
A1  - Weiss, Jan
A1  - Barner-Kowollik, Christopher
A1  - Laschewsky, André
T1  - Radical addition fragmentation chain transfer (RAFT) polymerization of ferrocenyl (meth)acrylates
JF  - Journal of polymer science : A, Polymer chemistry
N2  - We report on the controlled free radical homopolymerization of 1-ferrocenylethyl acrylate as well as of three new ferrocene bearing monomers, namely 4-ferrocenylbutyl acrylate, 2-ferrocenylamido-2-methylpropyl acrylate, and 4-ferrocenylbutyl methacrylate, by the RAFT technique. For comparison, the latter monomer was polymerized using ATRP, too. The ferrocene containing monomers were found to be less reactive than their analogues free of ferrocene. The reasons for the low polymerizability are not entirely clear. As the addition of free ferrocene to the reaction mixture did not notably affect the polymerizations, sterical hindrance by the bulky ferrocene moiety fixed on the monomers seems to be the most probable explanation. Molar masses found for 1-ferrocenylethyl acrylate did not exceed 10,000 g mol(-1), while for 4-ferrocenylbutyl (meth) acrylate molar masses of 15,000 g mol(-1) could be obtained. With PDIs as low as 1.3 in RAFT polymerization of the monomers, good control over the polymerization was achieved.
KW  - ferrocene
KW  - living radical polymerization (LRP)
KW  - monomers
KW  - radical addition fragmentation chain transfer (RAFT)
KW  - radical polymerization
KW  - redox polymers
KW  - synthesis
Y1  - 2012
U6  - https://doi.org/10.1002/pola.24994
SN  - 0887-624X
VL  - 50
IS  - 1
SP  - 108
EP  - 118
PB  - Wiley-Blackwell
CY  - Malden
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  -