Beuermann, Klaus Peter

[["dc.bibliographiccitation.firstpage","229"],["dc.bibliographiccitation.lastpage","239"],["dc.bibliographiccitation.seriesnr","206"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Gadermann, M."],["dc.contributor.author","Juergens, M."],["dc.contributor.author","Gunzler, F."],["dc.date.accessioned","2018-11-07T10:52:55Z"],["dc.date.available","2018-11-07T10:52:55Z"],["dc.date.issued","2004"],["dc.description.abstract","Free-radical terpolymerizations of styrene, methyl methacrylate, and glycidyl methacrylate were carried out in a tubular reactor in the presence of 20 wt.% CO2 at temperatures between 120 and 180degreesC and pressures of 300 and 350 bar. The number average molecular weights, M-N, were mostly between 2000 and 3000 g(.)mol(-1) and polydispersity indices around 2. In part of the experiments molecular weights were controlled by n-dodecyl mercaptan serving as the chain-transfer agent. PREDICI modeling indicates that the targeted molecular weights of M(N)similar to2500 g(.)mol(-1) and polydispersities around 2 may also be reached by using an initiator cocktail, a mixture of two initiators with significantly different decomposition rate coefficients. The predictions are confirmed experimentally."],["dc.identifier.doi","10.1002/masy.200450218"],["dc.identifier.isi","000220207400019"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49224"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-VCH"],["dc.publisher.place","Weinheim"],["dc.relation.conference","5th Conference on Polymer Reaction Engineering"],["dc.relation.crisseries","Macromolecular Symposia"],["dc.relation.eventend","2003-05-23"],["dc.relation.eventlocation","Quebec City, Canada"],["dc.relation.eventstart","2003-05-18"],["dc.relation.isbn","3-527-31039-8"],["dc.relation.ispartof","Polymer reaction engineering V"],["dc.relation.ispartofseries","Macromolecular symposia; 206"],["dc.title","Continuous styrene - methyl methacrylate - Glycidyl methacrylate terpolymerizations in homogeneous mixtures with supercritical carbon dioxide"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2151"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.lastpage","2160"],["dc.bibliographiccitation.volume","205"],["dc.contributor.author","Asua, J. M."],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Castignolles, P."],["dc.contributor.author","Charleux, B."],["dc.contributor.author","Giess, Rene MarkusGilbert, Robert G."],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Leiza, J. R."],["dc.contributor.author","Nikitin, A. N."],["dc.contributor.author","Vairon, J. P."],["dc.contributor.author","van Herk, A. M."],["dc.date.accessioned","2018-11-07T10:43:59Z"],["dc.date.available","2018-11-07T10:43:59Z"],["dc.date.issued","2004"],["dc.description.abstract","Propagation rate coefficients, k(P), for free-radical polymerization of butyl acrylate (BA) previously reported by several groups are critically evaluated. All data were determined by the combination of pulsed-laser polymerization (PLP) and subsequent polymer analysis by size exclusion (SEC) chromatography. The PLP-SEC technique has been recommended as the method of choice for the determination of k(P) by the IUPAC Working Party on Modeling of Polymerization Kinetics and Processes. Application of the technique to acrylates has proven to be very difficult and, along with other experimental evidence, has led to the conclusion that acrylate chain-growth kinetics are complicated by intramolecular transfer (backbiting) events to form a mid-chain radical structure of lower reactivity. These mechanisms have a significant effect on acrylate polymerization rate even at low temperatures, and have limited the PLP-SEC determination of k(P) of chain-end radicals to low temperatures (<20 degreesC) using high pulse repetition rates. Nonetheless, the values for BA from six different laboratories, determined at ambient pressure in the temperature range of -65 to 20 degreesC mostly for bulk monomer with few data in solution, fulfill consistency criteria and show excellent agreement, and are therefore combined together into a benchmark data set. The data are fitted well by an Arrhenius relation resulting in a pre-exponential factor of 2.21 x 10(7) L (.) mol(-1) (.) s(-1) and an activation energy of 17.9 kJ (.) mol(-1). It must be emphasized that these PLP-determined k(P) values are for monomer addition to a chain-end radical and that, even at low temperatures, it is necessary to consider the presence of two radical structures that have very different reactivity. Studies for other alkyl acrylates do not provide sufficient results to construct benchmark data sets, but indicate that the family behavior previously documented for alkyl methacrylates also holds true within the alkyl acrylate family of monomers. [GRAPHICS] Arrhenius plot of propagation rate coefficients, k(P), for BA as measured by PLP-SEC."],["dc.identifier.doi","10.1002/macp.200400355"],["dc.identifier.isi","000225139500002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/47174"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1022-1352"],["dc.title","Critically evaluated rate coefficients for free-radical polymerization, 5 - Propagation rate coefficient for butyl acrylate"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","002"],["dc.bibliographiccitation.journal","e-Polymers"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Drache, M."],["dc.contributor.author","Nelke, D."],["dc.contributor.author","Schmidt-Naake, G."],["dc.date.accessioned","2018-11-07T10:51:49Z"],["dc.date.available","2018-11-07T10:51:49Z"],["dc.date.issued","2004"],["dc.description.abstract","The differences in solubility of poly(vinyl acetate) (PVAc) and poly(methyl acrylate) (PMA) were addressed by applying atomistic Monte Carlo simulation techniques. Polymer segments consisting of nine monomer units serve as model compounds for polymer chains. As a measure of intermolecular interactions with the solvent environment, cohesion energies of the polymer segments embedded in either the corresponding monomer or in CO2 were calculated. Only in case of PMA segments in CO2 environment, specific interactions between polymer segments were identified. This finding is in agreement with experimental results on phase behaviour and propagation kinetics."],["dc.identifier.isi","000188374000001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48970"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","European Polymer Federation"],["dc.relation.issn","1618-7229"],["dc.title","Solvation of poly(methyl acrylate) and poly(vinyl acetate) by CO2 studied via atomistic Monte Carlo simulation techniques"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","184"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Macromolecules"],["dc.bibliographiccitation.lastpage","193"],["dc.bibliographiccitation.volume","39"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Hesse, P."],["dc.contributor.author","Lacik, Igor"],["dc.date.accessioned","2018-11-07T10:26:49Z"],["dc.date.available","2018-11-07T10:26:49Z"],["dc.date.issued","2006"],["dc.description.abstract","The propagation rate coefficient, k(p), for free-radical polymerization of nonionized methacrylic acid (MAA) in aqueous solution has been studied via pulsed laser polymerization (PLP) in conjunction with aqueous-phase size-exclusion chromatography (SEC). The PLP-SEC experiments were carried out between 20 and 80 degrees C within the entire concentration range from dilute solution containing 1 wt % MAA up to bulk MAA polymerization. The k(p) values which are determined under the assumption that the relevant monomer concentration at the radical site is identical to the known overall MAA concentration decrease by about 1 order of magnitude between 1 and 100 wt % MAA. This significant lowering is almost entirely due to a reduction in the Arrhenius preexponential factor, A(k(p)), whereas the activation energy, E-A(k(p)), stays essentially constant. The decrease in A(k(p)) is assigned to intermolecular interactions between the transition state (TS) structure for MAA propagation and an MAA environment being significantly stronger than the ones between this TS structure and an H2O environment. In an MAA-rich environment, the barrier to rotational motion of the relevant degrees of motion of the TS thus experiences enhanced friction, which is associated with a lowering of the preexponential factor and thus of k(p),"],["dc.identifier.doi","10.1021/ma051954i"],["dc.identifier.isi","000234500100030"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43124"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0024-9297"],["dc.title","Free-radical propagation rate coefficient of nonionized methacrylic acid in aqueous solution from low monomer concentrations to bulk polymerization"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","283"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Macromolecular Materials and Engineering"],["dc.bibliographiccitation.lastpage","293"],["dc.bibliographiccitation.volume","290"],["dc.contributor.author","Arita, T."],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Vana, P."],["dc.date.accessioned","2018-11-07T11:07:46Z"],["dc.date.available","2018-11-07T11:07:46Z"],["dc.date.issued","2005"],["dc.description.abstract","Reversible addition fragmentation chain transfer (RAFT) polymerizations of methyl acrylate (MA) in solution containing either 22 vol.-% CO2 or toluene were performed at 80 &DEG; C and 300 bar using cumyl dithiobenzoate (CDB) at concentrations between 1.8 x 10(-3) to 2.5 x 10(-2) mol (.) L-1 as the RAFT agent. Product molecular weight distributions and average molecular weights indicated the successful control of MA polymerization in CO2, even at low CDB concentrations. RAFT polymerization rates were strongly retarded by CDB and were in CO2 than in toluene solution. The enhanced fluidity associated with the addition of CO2 to the polymerizing system provided access to mechanistic details of RAFT polymerization. The data of the present study into MA, together with our recent results on RAFT polymerization of styrene in solution of CO2 and of toluene, suggest that self-termination of intermediate RAFT radicals is responsible for retardation in case of high concentrations of this intermediate and in case of enhanced fluidity, which may be achieved by polymerization in solution of CO2."],["dc.identifier.doi","10.1002/mame.200400274"],["dc.identifier.isi","000228888700008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52649"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1438-7492"],["dc.title","RAFT polymerization of methyl acrylate in carbon dioxide"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","876"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.lastpage","883"],["dc.bibliographiccitation.volume","205"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","El Rezzi, V."],["dc.contributor.author","Juergens, M."],["dc.contributor.author","Nelke, D."],["dc.date.accessioned","2018-11-07T10:49:01Z"],["dc.date.available","2018-11-07T10:49:01Z"],["dc.date.issued","2004"],["dc.description.abstract","Propagation kinetics of free-radical homopolymerizations of methyl acrylate, dodecyl acrylate, butyl methacrylate, dodecyl methacrylate, glycidyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate in solutions containing 40 wt.-% CO2 were studied applying the PLP-SEC technique. The obtained apparent propagation rate coefficients, k(p,app), are by up to 40% below the associated bulk k(p) values. This reduction is assigned to a lowering of local monomer concentration, c(M,loc), at the site of the free-radical chain end rather than to a decrease of the actual propagation rate coefficient. With the alkyl (meth)acrylates, intersegmental interactions between polar groups of the same polymer molecule are responsible for deviations of c(M,loc) from the analytical overall monomer concentration, c(M,a). Increasing size of the flexible alkyl ester group reduces the differences between c(M,loc) and C-M,C-a due to shielding effects. Methacrylates with cyclic ester groups do not follow this trend. In case of isobornyl methacrylate, which polymerizes to a rigid material with large side groups, relative size of monomer and CO2 matters and reduces c(M,loc) significantly below C-M,C-a."],["dc.identifier.doi","10.1002/macp.200400012"],["dc.identifier.isi","000221444500002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48329"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1022-1352"],["dc.title","Influence of monomer structure on the propagation kinetics of acrylate and methacrylate homopolymerizations studied via PLP-SEC in fluid CO2"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1355"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.lastpage","1364"],["dc.bibliographiccitation.volume","201"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Davis, T. P."],["dc.contributor.author","Giess, Rene MarkusGilbert, Robert G."],["dc.contributor.author","Hutchinson, Robin A."],["dc.contributor.author","Kajiwara, A."],["dc.contributor.author","Klumperman, B."],["dc.contributor.author","Russell, Gregory T."],["dc.date.accessioned","2018-11-07T10:33:19Z"],["dc.date.available","2018-11-07T10:33:19Z"],["dc.date.issued","2000"],["dc.description.abstract","Pulsed-laser polymerization (PLP) in conjunction with the analysis of the molecular weight distribution (MWD) via size-exclusion chromatography (SEC) remains recommended by the IUPAC Working Party on Modeling of polymerisation kinetics and processes as the method of choice for the determination of propagation rate coefficients, k(p), in free-radical polymerization. k(p) data from PLP-SEC studies in several laboratories for ethyl methacrylate (EMA), butyl methacrylate (BMA) and dodecyl methacrylate (DMA) bulk free-radical polymerizations at low conversion and ambient pressure are collected. The data fulfill consistency criteria and the agreement among the data is remarkable. These values are therefore recommended as constituting benchmark data sets for each monomer. The results are best fit by the following Arrhenius relations: EMA: k(p) = 10(6.61) L.mol(-1).s(-1) exp(-23.4 kJ.mol(-1)/R.T) BMA: k(p) = 10(6.58) L.mol(-1).s(-1) exp(-22.9 kJ.mol(-1)/R.T) DMA: k(p) = 10(6.40) L.mol(-1).s(-1) exp(-21.0 kJ.mol(-1)/R.T) For the methacrylates under investigation k(p) increases with the size of the ester group. For example, in going from MMA to DMA, k(p) at 50 degrees C is enhanced by a factor of 1.5."],["dc.identifier.doi","10.1002/1521-3935(20000801)201:12<1355::AID-MACP1355>3.0.CO;2-Q"],["dc.identifier.isi","000088962700023"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44582"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1022-1352"],["dc.title","Critically evaluated rate coefficients for free-radical polymerization, 3 - Propagation rate coefficients for alkyl methacrylates"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","PII S0079-6700(01)00049-1"],["dc.bibliographiccitation.firstpage","191"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Progress in Polymer Science"],["dc.bibliographiccitation.lastpage","254"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.date.accessioned","2018-11-07T10:31:41Z"],["dc.date.available","2018-11-07T10:31:41Z"],["dc.date.issued","2002"],["dc.description.abstract","Pulsed laser techniques have enormously improved the quality by which rate coefficients of individual steps in free-radical polymerization may be measured. Pulsed laser initiated polymerization (PLP) in conjunction with size-exclusion chromatography (SEC) yields the propagation rate coefficient, k(p). The PLP-SEC-technique has been applied to a wide variety of homopolymerizations and copolymerizations, either in bulk or in solution. In addition to reporting kinetic data, experimental details of PLP, of SEC, and of the limitations associated with the accurate determination of the MWD are discussed. The single pulse (SP)-PLP method, which combines PLP with time-resolved NLR spectroscopy, allows for a very detailed insight into the termination rate coefficient, k(t), for homo- and copolymerizations. k(t), data are reported as a function of temperature, pressure, monomer conversion, solvent concentration, and partly also of chain length. This review considers literature up to December 2000. (C) 2002 Elsevier Science Ltd. All rights reserved."],["dc.identifier.doi","10.1016/S0079-6700(01)00049-1"],["dc.identifier.isi","000174789400001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44170"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0079-6700"],["dc.title","Rate coefficients of free-radical polymerization deduced from pulsed laser experiments"],["dc.type","review"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY"],["dc.bibliographiccitation.volume","221"],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Juergens, M."],["dc.date.accessioned","2018-11-07T09:10:39Z"],["dc.date.available","2018-11-07T09:10:39Z"],["dc.date.issued","2001"],["dc.format.extent","U361"],["dc.identifier.isi","000168824802155"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26538"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.publisher.place","Washington"],["dc.relation.issn","0065-7727"],["dc.title","Free-radical copolymerizations of styrene and methacrylic acid esters in homogeneous phase of supercritical CO2."],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","433"],["dc.bibliographiccitation.issue","6-7"],["dc.bibliographiccitation.journal","Australian Journal of Chemistry"],["dc.bibliographiccitation.lastpage","437"],["dc.bibliographiccitation.volume","55"],["dc.contributor.author","Monteiro, Michael J."],["dc.contributor.author","Bussels, R."],["dc.contributor.author","Beuermann, S."],["dc.contributor.author","Buback, M."],["dc.date.accessioned","2018-11-07T10:32:48Z"],["dc.date.available","2018-11-07T10:32:48Z"],["dc.date.issued","2002"],["dc.description.abstract","Reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene was studied at high pressure, employing two dithioester RAFT agents with an isopropylcyano (5) and a cumyl (6) leaving group, respectively. The high-pressure reaction resulted in low polydispersity polymer. It was found that controlled polymerizations can be performed at increased pressures with a high degree of monomer conversion, which signifies that high-pressure polymerizations can be utilized for the production of higher molecular weight polystyrene of controlled microstructure. Retardation of styrene polymerization was also observed at high pressure in the presence of RAFT agents (5) and (6). It is postulated that the retarding potential of these two RAFT agents is associated with an intermediate radical termination mechanism. High-pressure free-radical polymerizations open the way to producing living polymers with high rates, and thus lower impurities such as 'dead' polymer that are formed through bimolecular termination reactions."],["dc.identifier.doi","10.1071/CH02079"],["dc.identifier.isi","000178056200009"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44441"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","C S I R O Publishing"],["dc.publisher.place","Collingwood"],["dc.relation.conference","25th Australasian Polymer Symposium"],["dc.relation.eventlocation","UNIV NEW ENGLAND, ARMIDALE, AUSTRALIA"],["dc.relation.issn","0004-9425"],["dc.title","High-pressure 'living' free-radical polymerization of styrene in the presence of RAFT"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]