| dc.contributor.advisor | Buback, Michael Prof. Dr. | |
| dc.contributor.author | Sörensen, Nicolai | |
| dc.date.accessioned | 2015-10-28T09:36:31Z | |
| dc.date.available | 2015-10-28T09:36:31Z | |
| dc.date.issued | 2015-10-28 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-0023-9662-7 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-5336 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-5336 | |
| dc.language.iso | eng | de |
| dc.publisher | Niedersächsische Staats- und Universitätsbibliothek Göttingen | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 540 | de |
| dc.title | Kinetics and Mechanism of Cu-Catalyzed Atom Transfer Radical Polymerization | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Buback, Michael Prof. Dr. | |
| dc.date.examination | 2015-05-26 | |
| dc.description.abstracteng | The kinetics and mechanism of Cu-mediated atom transfer radical polymerization (ATRP)
were investigated with particular emphasis on the ATRP deactivation rate coefficient,
k_deact
. The method of pulsed laser polymerization (PLP) induced by a laser single pulse
(SP–PLP) was applied in conjunction with electron paramagnetic resonance (EPR) for the
analysis of radical concentration. As the ATRP equilibrium is superimposed on a
conventional radical polymerization scheme, the decay of radical concentration after
instantaneous laser-induced production of an intense burst of radicals occurs as a
consequence of both deactivation and radical-radical termination. The measurement of
k_deact
thus consists of two steps: First, termination is measured via SP–PLP–EPR for the
Cu-free monomer system. Within a second step, the decay of radical concentration is
monitored with the Cu(II) complex being present.
The novel strategy has been applied to homopolymerizations of butyl acrylate (BA) and
dodecyl methacrylate (DMA). HMTETA, PMDETA and TPMA were selected as the
ligands to Cu. The first two are a linear tri- and a tetradentate ligand, respectively, whereas
TPMA is a branched tetradentate ligand.
In the Cu-free DMA system, the crossover chain length i_c
showed a strong decrease toward
higher temperature. It is the first time that a temperature effect on i_c was observed.
In case of DMA polymerization with TPMA, k_deact was found in close agreement with the
number for the monomer-free model systems, whereas with HMTETA and PMDETA,
k_deact for the polymerizing system was lower by about one order of magnitude which effect
is assigned to steric strain on the polymer chain due to the α-methyl group. The values of
k_deact for BA polymerization are close to the ones determined for the model system.
With BA, an additional reaction channel occurs in which the Cu(I)
species reacts with
acrylate radicals. Thus, SP–PLP–EPR experiments on BA in the presence of an ATRP Cu
catalyst were performed and the produced Cu(II)
species was detected. In addition, timeresolved
spectra
were
recorded.
The
results
suggest
that
the
formation
of
organometallic
species
mainly
depends
on the ligand
to
Cu
and is
enhanced
for
highly
active
catalysts. | de |
| dc.contributor.coReferee | Vana, Philipp Prof. Dr. | |
| dc.subject.eng | atom-transfer radical polymerization (ATRP) | de |
| dc.subject.eng | reversible-deactivated radical polymerization (RDRP) | de |
| dc.subject.eng | copper | de |
| dc.subject.eng | deactivation | de |
| dc.subject.eng | termination | de |
| dc.subject.eng | chain-length dependence | de |
| dc.subject.eng | electron paramagnetic resonance (EPR) | de |
| dc.subject.eng | kinetics | de |
| dc.subject.eng | spectroscopy | de |
| dc.subject.eng | pulsed-laser polymerization (PLP) | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-0023-9662-7-2 | |
| dc.affiliation.institute | Fakultät für Chemie | de |
| dc.subject.gokfull | Chemie (PPN62138352X) | de |
| dc.identifier.ppn | 837983355 | |