title: Propagation rate coefficients for homogeneous phase VDF-HFP copolymerization in supercritical CO2.
abstract: For the first time, propagation rate coefficients, k(p,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 CO(2) as solvent for temperatures ranging from 45 to 90 °C. Absolute polymer molecular weights were calculated on the basis of experimentally determined Mark-Houwink constants. The Arrhenius parameters of k(p,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.
authors.affiliation: Institute of Chemistry, University of Potsdam, Potsdam/Golm, Germany.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Siegmann
authors.forename: Eléonore
authors.initials: E
authors.lastname: Möller
authors.forename: Sabine
authors.initials: S
authors.lastname: Beuermann
mesh_terms: D025924:Chromatography, Supercritical Fluid; D005466:Fluorocarbons / Q000737:chemistry*; D007700:Kinetics; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D005466:Fluorocarbons; D011108:Polymers; D014753:Vinyl Compounds; C031235:hexafluoropropene; C007384:1,1-difluoroethylene