TY - JOUR A1 - Cockburn, Robert A. A1 - Siegmann, Rebekka A1 - Payne, Kevin A. A1 - Beuermann, Sabine A1 - McKenna, Timothy F. L. A1 - Hutchinson, Robin A. T1 - Free Radical Copolymerization Kinetics of gamma-Methyl-alpha-methylene-gamma-butyrolactone (MeMBL) JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - The propagation kinetics and copolymerization behavior of the biorenewable monomer gamma-methyl-alpha-methylene-gamma-butyrolactone (MeMBL) are studied using the Pulsed laser polymerization (PLP)/size exclusion chromatography (SEC) technique. The propagation rate coefficent for MeMBL is 15% higher than that of its structural analogue, methyl methacrylate (MMA), with a similar activation energy of 21.8 kJ . mol(-1). When compared to MMA, MeMBL is preferentially incorporated into copolymers when reacted with styrene (ST), MMA, and n-butyl acrylate (BA); the monomer reactivity ratios fit from bulk MeMBL/ST, MeMBL/MMA, and MeMBL/BA copolymerizations are r(MeMBL) = 0.80 +/- 0.04 and r(ST) = 0.34 +/- 0.04, r(MeMBL), = 3.0 +/- 0.3 and r(MMA) = 0.33 +/- 0.01, and r(MeMBL) = 7.0 +/- 2.0 and r(BA) = 0.16 +/- 0.03, respectively. In all cases, no significant variation with temperature was found between 50 and 90 degrees C. The implicit penultimate unit effect (IPUE) model was found to adequately fit the composition-averaged copolymerization propagation rate coefficient, k(p,cop), for the three systems. Y1 - 2011 U6 - https://doi.org/10.1021/bm200400s SN - 1525-7797 VL - 12 IS - 6 SP - 2319 EP - 2326 PB - American Chemical Society CY - Washington 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 - 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 - Vukicevic, Radovan A1 - Beuermann, Sabine T1 - Fullerenes decorated with poly(vinylidene fluoride) JF - Macromolecules : a publication of the American Chemical Society N2 - Fullerenes decorated with poly(vinylidene fluoride) (PVDF) were synthesized in a three-step procedure: Iodine transfer polymerization of vinylidene fluoride with C(6)F(12)I(2) as the chain transfer agent was carried out in supercritical carbon dioxide to synthesize iodine-terminated PVDF, which was subsequently transformed to azide-terminated polymer. Finally, azide-terminated PVDF chains were attached to a fullerene core under microwave irradiation at 160 degrees C in 1.5 h. The materials were characterized by NMR, FT-IR, UV/vis, GPC, elemental analysis, and DSC. On average, 4-5 PVDF chains are attached to one C(60) moiety. FT-IR spectra and DSC measurements indicate that the polymer end groups strongly affect the crystallinity of the material. For PVDF with azide end groups and PVDF attached to fullerenes the fraction of the beta polymorph is dominant while alpha polymorphs are almost absent. Y1 - 2011 U6 - https://doi.org/10.1021/ma102754c SN - 0024-9297 VL - 44 IS - 8 SP - 2597 EP - 2603 PB - American Chemical Society CY - Washington ER - TY - CHAP A1 - Vukicevic, Radovan A1 - Schreiber, Ulrike A1 - Beuermann, Sabine T1 - Azide-terminated poly(vinylidene fluoride) as building block for nanocomposite materials and block copolymers T2 - Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS Y1 - 2011 SN - 0065-7727 VL - 242 IS - 16 PB - American Chemical Society CY - Washington ER - TY - CHAP A1 - Schreiber, Ulrike A1 - Vukicevic, Radovan A1 - Beuermann, Sabine T1 - Block copolymers of poly(vinylidene fluoride) obtained via 1,3 dipolar cycloaddition T2 - Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS Y1 - 2011 SN - 0065-7727 VL - 242 PB - American Chemical Society CY - Washington 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 - 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 - TY - JOUR A1 - Schreiber, Ulrike A1 - Hosemann, Benjamin A1 - Beuermann, Sabine T1 - 1H,1H,2H,2H-Perfluorodecyl-Acrylate-Containing block copolymers from ARGET ATRP JF - Macromolecular chemistry and physics N2 - Block copolymers of 1H,1H,2H,2H-perfluorodecyl acrylate (AC8) were obtained from ARGET ATRP. To obtain block copolymers of low dispersity the PAC8 block was synthesized in anisole with a CuBr(2)/PMDETA catalyst in the presence of tin(II) 2-ethylhexanoate as a reducing agent. The PAC8 block was subsequently used as macroinitiator for copolymerization with butyl and tert-butyl acrylate carried out in scCO(2). To achieve catalyst solubility in CO(2) two fluorinated ligands were employed. The formation of block copolymers was confirmed by size exclusion chromatography and DSC. KW - atom transfer radical polymerization (ATRP) KW - block copolymers KW - fluoropolymers KW - supercritical carbon dioxide Y1 - 2011 U6 - https://doi.org/10.1002/macp.201000307 SN - 1022-1352 VL - 212 IS - 2 SP - 168 EP - 179 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Goebel, Ronald A1 - Hesemann, Peter A1 - Weber, Jens A1 - Moeller, Eléonore A1 - Friedrich, Alwin A1 - Beuermann, Sabine A1 - Taubert, Andreas T1 - Surprisingly high, bulk liquid-like mobility of silica-confined ionic liquids N2 - Mesoporous silica monoliths were prepared by the sol - gel technique and. lled with 1-ethyl-3-methyl imidazolium [Emim]-X (X = dicyanamide [N(CN)(2)], ethyl sulfate [EtSO4], thiocyanate [SCN], and triflate [TfO]) ionic liquids (ILs) using a methanol-IL exchange technique. The structure and behavior of the ILs inside the silica monoliths were studied using X-ray scattering, nitrogen sorption, IR spectroscopy, solid-state NMR, and thermal analysis. DSC finds shifts in both the glass transition temperature and melting points (where applicable) of the ILs. Glass transition and melting occur well below room temperature. There is thus no conflict with the NMR and IR data, which show that the ILs are as mobile at room temperature as the bulk (not confined) ILs. The very narrow line widths of the NMR spectra suggest that the ILs in our materials have the highest mobility reported for confined ILs so far. As a result, our data suggest that it is possible to generate IL/silica hybrid materials (ionogels) with bulk-like properties of the IL. This could be interesting for applications in, e.g., the solar cell or membrane fields. Y1 - 2009 UR - http://xlink.rsc.org/jumptojournal.cfm?journal_code=CP U6 - https://doi.org/10.1039/B821833a SN - 1463-9076 ER - TY - JOUR A1 - Xie, Zai-Lai A1 - Jelicic, Aleksandra A1 - Wang, Feipeng A1 - Rabu, Pierre A1 - Friedrich, Alwin A1 - Beuermann, Sabine A1 - Taubert, Andreas T1 - Transparent, flexible, and paramagnetic ionogels based on PMMA and the iron-based ionic liquid 1-butyl-3- methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4] N2 - The iron-containing ionic liquid (IL) 1-butyl-3-methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4] has been used as a building block in the synthesis of transparent, ion-conducting, and paramagnetic ionogels. UV/Vis spectroscopy shows that the coordination around the Fe(III) ion does slightly change upon incorporation of the IL into PMMA. The thermal stability of the PMMA increases significantly with IL incorporation. In particular, the onset weight loss observed at ca. 265 degrees C for pure PMMA is completely suppressed. The ionic conductivity shows a strong temperature dependence and increases with increasing IL weight fractions. The magnetic properties are similar to those reported for the pure IL and are not affected by the incorporation into the PMMA matrix. The resulting ionogel is thus an interesting prototype for soft, flexible, and transparent materials combining the mechanical properties of the matrix with the functionality of the metal-containing IL, such as magnetism. Y1 - 2010 UR - http://www.rsc.org/Publishing/Journals/jm/index.asp U6 - https://doi.org/10.1039/C0jm01733g SN - 0959-9428 ER -