Buback, Michael M.

[["dc.bibliographiccitation.firstpage","128970"],["dc.bibliographiccitation.journal","Chemical Engineering Journal"],["dc.bibliographiccitation.volume","415"],["dc.contributor.author","Zapata-Gonzalez, Ivan"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Rivera-Magallanes, Axel"],["dc.date.accessioned","2021-06-01T09:41:13Z"],["dc.date.available","2021-06-01T09:41:13Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1016/j.cej.2021.128970"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/84850"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.relation.issn","1385-8947"],["dc.title","Kinetic importance of the missing step in dithiobenzoate-mediated RAFT polymerizations of acrylates"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1400"],["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.lastpage","1409"],["dc.bibliographiccitation.volume","212"],["dc.contributor.author","Schrooten, Jens"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Hesse, Pascal"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Lacik, Igor"],["dc.date.accessioned","2018-11-07T08:54:42Z"],["dc.date.available","2018-11-07T08:54:42Z"],["dc.date.issued","2011"],["dc.description.abstract","Termination kinetics of 1-vinylpyrrolidin-2-one radical polymerization in aqueous solution has been studied at 40 degrees C between 20 and 100 wt.-% VP. The /k(p) values from laser single-pulse experiments with microsecond time-resolved NIR detection of monomer conversion, in conjunction with k(p) from literature, yield chain-length-averaged termination rate coefficients, . Because of better signal-to-noise quality, experiments were carried out at 2 000 bar, but also at 1 500, 1 000, and 500 bar, thus allowing for estimates of at ambient pressure. The dependence of on monomer conversion indicates initial control by segmental diffusion followed by translational diffusion and finally reaction diffusion control. To assist the kinetic studies, viscosities of VP-water mixtures at ambient pressure have been determined."],["dc.description.sponsorship","BASF SE"],["dc.identifier.doi","10.1002/macp.201100021"],["dc.identifier.isi","000292541600008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22734"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1022-1352"],["dc.title","Termination Kinetics of 1-Vinylpyrrolidin-2-one Radical Polymerization in Aqueous Solution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","8197"],["dc.bibliographiccitation.issue","21"],["dc.bibliographiccitation.journal","Industrial & Engineering Chemistry Research"],["dc.bibliographiccitation.lastpage","8204"],["dc.bibliographiccitation.volume","47"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Hesse, Pascal"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Kasak, Peter"],["dc.contributor.author","Lacik, Igor"],["dc.contributor.author","Stach, Marek"],["dc.contributor.author","Utz, Inga"],["dc.date.accessioned","2018-11-07T11:09:14Z"],["dc.date.available","2018-11-07T11:09:14Z"],["dc.date.issued","2008"],["dc.description.abstract","The batch free-radical polymerization of nonionized methacrylic acid (MAA) in aqueous solution has been investigated at 50 degrees C and initial monomer concentrations Lip to 30 wt % MAA. The rate of conversion increases as the initial weight fraction of MAA decreases, a result explained by the dependence of the propagation rate coefficient, k(p), on monomer concentration. The conversion profiles measured at different MAA and initiator levels are represented by a polymerization model with con version-dependent k(p) taken from literature, and the termination rate coefficient, k(1), represented by a function including terms for segmental diffusion, translational diffusion, and reaction diffusion. The model includes chain transfer to monomer and is capable of representing polymer molecular weight averages and distributions, with the better fit obtained assuming that the transfer rate coefficient also varies with monomer concentration."],["dc.identifier.doi","10.1021/ie800887v"],["dc.identifier.isi","000260534600031"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52961"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0888-5885"],["dc.title","Kinetics and Modeling of Free-Radical Batch Polymerization of Nonionized Methacrylic Acid in Aqueous Solution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3244"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Macromolecules"],["dc.bibliographiccitation.lastpage","3253"],["dc.bibliographiccitation.volume","49"],["dc.contributor.author","Lacik, Igor"],["dc.contributor.author","Chovancova, Anna"],["dc.contributor.author","Uhelska, Lucia"],["dc.contributor.author","Preusser, Calista"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Buback, Michael"],["dc.date.accessioned","2018-11-07T10:14:21Z"],["dc.date.available","2018-11-07T10:14:21Z"],["dc.date.issued","2016"],["dc.description.abstract","Acrylamide (AAm) is an important water-soluble monomer. Pulsed-laser polymerization in conjunction with size-exclusion chromatography (PLP-SEC) has been employed to measure the propagation rate coefficient, k(p), in aqueous solution at monomer concentrations from 1 to 30 wt % and temperatures between 5 and 70 degrees C. Laser pulse repetition rate has been extensively varied, from 25 up to 500 Hz, to check for consistency of the measured k(p) values, which increase toward larger water content, e.g., by 50% upon lowering AAm concentration from 30 to 5 wt %. Variation of pH, up to pH 11, and addition of up to 1 mol L-1 NaCl to the polymerizing system do not significantly affect k(p). The activation energy, E-A(k(p)), of about 18 kJ mol(-1) stays more or less constant within the monomer concentration range under investigation, which indicates that the changes of k(p) are primarily of entropic origin. The pre-exponential factor, A(k(p)), increases from 5.7 X 10(7) to 7.7 X 10(7) L mol(-1) s(-1) upon lowering the AAm concentration from 30 to 10 wt %. These high A(k(p)) numbers demonstrate the fluidizing action of water,on the transition state toward internal rotation with AAm being lower than with acrylates."],["dc.identifier.doi","10.1021/acs.macromol.6b00526"],["dc.identifier.isi","000375809700005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40604"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","1520-5835"],["dc.relation.issn","0024-9297"],["dc.title","PLP-SEC Studies into the Propagation Rate Coefficient of Acrylamide Radical Polymerization in Aqueous Solution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","204"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Polymer Chemistry"],["dc.bibliographiccitation.lastpage","212"],["dc.bibliographiccitation.volume","5"],["dc.contributor.author","Barner-Kowollik, Christopher"],["dc.contributor.author","Beuermann, Sabine"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Castignolles, Patrice"],["dc.contributor.author","Charleux, Bernadette"],["dc.contributor.author","Coote, Michelle L."],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Junkers, Thomas"],["dc.contributor.author","Lacik, Igor"],["dc.contributor.author","Russell, Gregory T."],["dc.contributor.author","Stach, Marek"],["dc.contributor.author","van Herk, Alex M."],["dc.date.accessioned","2018-11-07T09:47:19Z"],["dc.date.available","2018-11-07T09:47:19Z"],["dc.date.issued","2014"],["dc.description.abstract","Propagation rate coefficient (k(p)) data for radical polymerization of methyl acrylate (MA) in the bulk are critically evaluated and a benchmark dataset is put forward by a task-group of the IUPAC Subcommittee on Modeling of Polymerization Kinetics and Processes. This dataset comprises previously published results from three laboratories as well as new data from a fourth laboratory. Not only do all these values of k(p) fulfill the recommended consistency checks for reliability, they are also all in excellent agreement with each other. Data have been obtained employing the technique of pulsed-laser polymerization (PLP) coupled with molar-mass determination by size-exclusion chromatography (SEC), where PLP has been carried out at pulse-repetition rates of up to 500 Hz, enabling reliable k(p) to be obtained through to 60 degrees C. The best-fit - and therefore recommended - Arrhenius parameters are activation energy E-A - 17.3 kJ mol(-1) and pre-exponential (frequency) factor A - 1.41 x 10(7) L mol(-1) s(-1). These hold for secondary-radical propagation of MA, and may be used to calculate effective propagation rate coefficients for MA in situations where there is a significant population of mid-chain radicals resulting from backbiting, as will be the case at technically relevant temperatures. The benchmark dataset reveals that k(p) values for MA obtained using PLP in conjunction with MALDI-ToF mass spectrometry are accurate. They also confirm, through comparison with previously obtained benchmark k(p) values for n-butyl acrylate, methyl methacrylate and n-butyl methacrylate, that there seems to be identical family-type behavior in n-alkyl acrylates as in n-alkyl methacrylates. Specifically, k(p) for the n-butyl member of each family is about 20% higher than for the corresponding methyl member, an effect that appears to be entropic in origin. Furthermore, each family is characterized by an approximately constant E-A, where the value is 5 kJ mol(-1) lower for acrylates."],["dc.description.sponsorship","IUPAC [2011-034-2-400]"],["dc.identifier.doi","10.1039/c3py00774j"],["dc.identifier.isi","000327669900025"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35083"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Royal Soc Chemistry"],["dc.relation.issn","1759-9962"],["dc.relation.issn","1759-9954"],["dc.title","Critically evaluated rate coefficients in radical polymerization-7. Secondary-radical propagation rate coefficients for methyl acrylate in the bulk"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","95"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Macromolecular Reaction Engineering"],["dc.bibliographiccitation.lastpage","107"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Wittenberg, Nils F. G."],["dc.contributor.author","Preusser, Calista"],["dc.contributor.author","Kattner, Hendrik"],["dc.contributor.author","Stach, Marek"],["dc.contributor.author","Lacik, Igor"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Buback, Michael"],["dc.date.accessioned","2018-11-07T10:16:03Z"],["dc.date.available","2018-11-07T10:16:03Z"],["dc.date.issued","2016"],["dc.description.abstract","Batch radical polymerization of 5-40wt% non-ionized acrylic acid (AA) in aqueous solution has been studied between 35 and 90 degrees C under variation of initiator concentration and type as well as upon addition of different levels of 2-mercaptoethanol as chain-transfer agent (CTA). Chain-length-dependent termination was taken into account in a model developed to describe the system, as high amounts of CTA have an impact on polymerization kinetics due to reduced chain length. The model also considers the 1,5-hydrogen shift (backbiting) reaction that transforms the secondary propagating radical into a tertiary midchain radical, with the backbiting reaction quantified via C-13 NMR. The model developed is the most comprehensive treatment to date of this complex polymerization system and is able to represent monomer conversion profiles and polymer molar mass distributions over a wide range of conditions."],["dc.identifier.doi","10.1002/mren.201500017"],["dc.identifier.isi","000374562200001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40956"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1862-8338"],["dc.relation.issn","1862-832X"],["dc.title","Modeling Acrylic Acid Radical Polymerization in Aqueous Solution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","8631"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Macromolecules"],["dc.bibliographiccitation.lastpage","8641"],["dc.bibliographiccitation.volume","40"],["dc.contributor.author","Nikitin, Anatoly N."],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Hesse, Pascal"],["dc.date.accessioned","2018-11-07T10:51:34Z"],["dc.date.available","2018-11-07T10:51:34Z"],["dc.date.issued","2007"],["dc.description.abstract","A novel method to extract individual free-radical polymerization rate coefficients for butyl acrylate intramolecular chain transfer (backbiting), k(bb), and for monomer addition to the resulting midchain radical, k(p)(t), is presented. The approach for measuring k(bb) does not require knowledge of any other rate coefficient. Only the dispersion parameter of SEC broadening has to be determined by fitting measured MWDs or should be available from separate experiments. The method is based upon analysis of the shift in the position of the inflection point of polymer molecular weight distributions produced by a series of pulsed-laser polymerization (PLP) experiments with varying laser pulse repetition rate. The coefficient k(bb) is determined from the onset of the sharp decrease of the apparent propagation rate coefficient (k(p)(app)) with decreasing repetition rate, an approach verified by simulation. With experiments performed between -10 and +30 degrees C, the estimated values are fitted well by an Arrhenius relation with pre-exponential factor A(k(bb)) = (4.84 +/- 0.29) x 10(7) s(-1) and activation energy E-a(k(bb)) = (31.7 +/- 2.5) kJ center dot mol(-1). At low pulse repetition rates, the experimental k(p)(app) values are related to an averaged propagation rate coefficient, k(p)(av), that is dependent on the relative population of chain-end and midchain radicals. Evaluated by comparing simulated and experimental molecular weight distributions, k(p)(av) provides an estimate for k(p)(t). The Arrhenius parameters are: A(k(p)(t)) = (1.52 +/- 0.14) x 10(6) L center dot mol(-1)center dot s(-1) and E-a(k(p)(t)) = (28.9 +/- 3.2) kJ center dot mol(-1)."],["dc.identifier.doi","10.1021/ma071413o"],["dc.identifier.isi","000251094500022"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48923"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0024-9297"],["dc.title","Determination of intramolecular chain transfer and midchain radical propagation rate coefficients for butyl acrylate by pulsed laser polymerization"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","UNSP 1600357"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.volume","218"],["dc.contributor.author","Barner-Kowollik, Christopher"],["dc.contributor.author","Beuermann, Sabine"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Junkers, Thomas"],["dc.contributor.author","Kattner, Hendrik"],["dc.contributor.author","Manders, Bart"],["dc.contributor.author","Nikitin, Anatoly N."],["dc.contributor.author","Russell, Gregory T."],["dc.contributor.author","van Herk, Alex M."],["dc.date.accessioned","2018-11-07T10:29:14Z"],["dc.date.available","2018-11-07T10:29:14Z"],["dc.date.issued","2017"],["dc.description.abstract","Propagation rate coefficient values, k(p), reported by several groups for radical polymerization of bulk vinyl acetate are critically evaluated. All data are obtained by the combination of pulsed-laser polymerization and subsequent polymer analysis by size exclusion chromatography, as recommended by the IUPAC Working Party on Modeling of Polymerization Kinetics and Processes. Although a small (approximate to 15%) increase in k(p) is observed as laser pulse repetition rate is increased from low (25-100 Hz) to high (300-500 Hz) values, all of the data fulfill the required consistency criteria and thus are combined into a benchmark set covering the temperature range of 5-70 degrees C. The data are fitted well by an Arrhenius relation resulting in a pre-exponential factor of 1.35 x 10(7) L mol(-1) s(-1) and an activation energy of 20.4 kJ mol(-1), with 95% confidence ellipsoids for the parameters also presented."],["dc.description.sponsorship","IUPAC [2013-045-1-400]"],["dc.identifier.doi","10.1002/macp.201600357"],["dc.identifier.isi","000393411000011"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43599"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1521-3935"],["dc.relation.issn","1022-1352"],["dc.title","Critically Evaluated Rate Coefficients in Radical Polymerization-8. Propagation Rate Coefficients for Vinyl Acetate in Bulk"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2327"],["dc.bibliographiccitation.issue","23"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.lastpage","2336"],["dc.bibliographiccitation.volume","215"],["dc.contributor.author","Uhelska, Lucia"],["dc.contributor.author","Chorvat, Dusan"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Santanakrishnan, Sandhya"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Lacik, Igor"],["dc.date.accessioned","2018-11-07T09:32:04Z"],["dc.date.available","2018-11-07T09:32:04Z"],["dc.date.issued","2014"],["dc.description.abstract","Pulsed-laser polymerization with subsequent analysis of the polymer molar mass distribution by size-exclusion chromatography, PLP-SEC, is used to measure the propagation rate coefficient, k(p), of N-vinylpyrrolidone (NVP) in a series of organic solvents, varying the NVP concentration from 5 to 100 wt% and varying the temperature between-5 and +80 degrees C. In contrast to the 20-fold increase observed in aqueous solution upon decreasing the NVP concentration from bulk to dilute conditions, the k(p) values of NVP in butyl acetate, iso-propyl acetate, N-ethylpyrrolidone, and N-ethylformamide stay within 20% of the bulk value and exhibit no significant dependence on monomer concentration. The k(p) behavior of NVP in methanol and n-butanol is intermediate between the one in water and in the other organic solvents, with k(p) increasing by about a factor of 2 upon lowering the monomer concentration from bulk to 5 wt% NVP. The activation energies for propagation in organic solvents agree within experimental uncertainty with the value reported for bulk NVP. The data demonstrate that hydrogen bonding is responsible for the increase in k(p) upon dilution, with this effect being much stronger in an aqueous environment than in a solution of alcohol."],["dc.identifier.doi","10.1002/macp.201400329"],["dc.identifier.isi","000345966900006"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31665"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1521-3935"],["dc.relation.issn","1022-1352"],["dc.title","Radical Propagation Kinetics of N-Vinylpyrrolidone in Organic Solvents Studied by Pulsed-Laser Polymerization-Size-Exclusion Chromatography (PLP-SEC)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3513"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Macromolecules"],["dc.bibliographiccitation.lastpage","3520"],["dc.bibliographiccitation.volume","41"],["dc.contributor.author","Beuermann, Sabine"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Hesse, Pascal"],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Kukucova, Silvia"],["dc.contributor.author","Lacik, Igor"],["dc.date.accessioned","2018-11-07T11:15:00Z"],["dc.date.available","2018-11-07T11:15:00Z"],["dc.date.issued","2008"],["dc.description.abstract","The termination kinetics of free-radical polymerization of nonionized methacrylic acid (MAA) in aqueous solution has been investigated at two MAA concentrations, 30 and 60 wt %, by single-pulse pulsed-laser initiated polymerization carried out in conjunction with mu s time-resolved in-line monitoring of monomer conversion via near-infrared spectroscopy (SP-PLP-NIR). From measured values of k(t)/k(p) for 2000 bar, with the conversion-dependent propagation rate coefficient, k(p), being inferred from literature data, the chain-length-averaged termination rate coefficient, < k(t)>, is deduced as a function of monomer conversion, x. As with methyl methacrylate polymerization, the < k(t)> vs x dependence may be modeled under the assumption that, toward higher degrees of monomer conversion, < k(t)> is successively controlled by segmental diffusion, translational diffusion, and reaction diffusion. For 50 degrees C, 2000 bar, and initial monomer concentrations in water of 30 and 60 wt %, chemically initiated polymerizations have also been carried out. The resulting < k(t)> values are in good agreement with the data from SP-PLP-NIR."],["dc.identifier.doi","10.1021/ma7028902"],["dc.identifier.isi","000256058000020"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54273"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0024-9297"],["dc.title","Termination kinetics of the free-radical polymerization of nonionized methacrylic acid in aqueous solution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]