title: Determining Free-Radical Propagation Rate Coefficients with High-Frequency Lasers: Current Status and Future Perspectives.
abstract: Detailed knowledge of the polymerization mechanisms and kinetics of academically and industrially relevant monomers is mandatory for the precision synthesis of tailor-made polymers. The IUPAC-recommended pulsed-laser polymerization-size exclusion chromatography (PLP-SEC) approach is the method of choice for the determination of propagation rate coefficients and the associated Arrhenius parameters for free radical polymerization processes. With regard to specific monomer classes-such as acrylate-type monomers, which are very important from a materials point of view-high laser frequencies of up to 500 Hz are mandatory to prevent the formation of mid-chain radicals and the occurrence of chain-breaking events by chain transfer, if industrially relevant temperatures are to be reached and wide temperature ranges are to be explored (up to 70 °C). Herein the progress and state-of-the-art of high-frequency PLP-SEC with pulse repetition rates of 500 Hz is reported, with a critical collection of to-date investigated 500 Hz data as well as future perspectives for the field.
authors.affiliation: Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76128, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Karlsruhe, Germany.
authors.forename: Katrin B
authors.initials: KB
authors.lastname: Kockler
authors.affiliation: Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76128, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Karlsruhe, Germany.
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Haehnel
authors.affiliation: Polymer Reaction Design Group, Institute for Materials Research, Universiteit Hasselt, Martelarenlaan 42, B-3500, Hasselt, Belgium.|IMEC associated lab IMOMEC, Wetenschapspark 1, B-3590, Diepenbeek, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Junkers
authors.affiliation: Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76128, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Karlsruhe, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Barner-Kowollik
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D000180:Acrylic Resins / Q000737:chemistry*; D002850:Chromatography, Gel; D005609:Free Radicals / Q000737:chemistry; D006358:Hot Temperature; D007700:Kinetics; D007834:Lasers; D058105:Polymerization; D013816:Thermodynamics
chemical_list: D000179:Acrylates; D000180:Acrylic Resins; D005609:Free Radicals; C006903:carbopol 940; C036658:acrylic acid
keywords: PLP-SEC; free radical polymerization; free radicals; lasers; propagation rate coefficients; pulsed laser polymerization; size exclusion chromatography