TY  - THES
AB  - A systematic synthesis for coil-rod-coil(c-r-c) block copolymers with differing material characteristics should lead to the usage of c-r-c block copolymers as surface probes and for the
study of the self assembling behavior of c-r-c block copolymers. Therefor 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) based alkoxyamines with covalently attached
NMR probes where synthesized starting from nitroxides and functionalized styrenes. These
alkoxyamines were used as initiators for the synthesis of copolymers of styrene with
3-(tert -butoxy)-3-oxopropyl-, chloromethyl-, hydroxymethyl- and 3-hydroxypropyl- substituted styrenes as well as vinylpyridine. Additionally to these copolymers the homopolymer poly(4-hydroxymethyl-styrene) was synthesized using nitroxide mediated polymerisation (NMP). For the buildup of the NMR-probe carrying alkoxyamines TIPNO, two TIPNO
derivatives, one with an ethoxy and one with a trifluoro-methoxy, and methoxy substituted
styrenes were used. In contrast to the GPC analysis, where a polymer standard as reference is necessary to determine the molecular weight of polymers the analysis of polymers
via NMR spectroscopy does not need a calibration. The chemical shift of the methoxy protons is located at 3.5-4.0 ppm and the signal can be integrated separately from all other
signals of the used alkoxyamines and the synthesized polymers. This allows to determine
the degree of polymerization and the degree of co-polymerization, even when the structure of the (co)polymer differs from any purchasable standard. Additionally, TIPNO-based
alkoxyamines with bromo and protected alkynyl substituents were synthesized. These
functional groups allowing further modification. The bromo derivative was converted into
the carbonic acid and the iodo derivative via halogen metal exchange followed by reaction with CO2 or I2. The alkoxyamines with halogen and the deprotected alkyne function
were used for Sonogashira-Hagihara cross-couplings with oligo(p-phenyleneethynylene)
(OPPE) rods to obtain rod-shaped NMP initiators. Additionaly, the alkyne group was used
for copper catalyzed [2+3] cycloadditions with azides. With these alkoxyamines copolymers of styrene and styrene derivatives where synthesized to obtain r-c block copolymers
with varying coil segments. Through further reactions of the r-c block copolymers c-rc block copolymers were synthesized. It was known that the conversion of a copper
catalyzed oxidative dimerisation of two r-c block copolymers originated from a TIPS protected r-c block copolymer is not quantitative. The key step of synthesizing c-r-c block
copolymers was the use of (3-Cyanopropyl)dimethylsilyl(CPDMS)-group instead of TIPS
as protecting group at the used OPPE. By using the CPDMS group the alkyne deprotection
and dimerisation led to a nearly quantitative conversation of dimerisation reaction.
DA  - 2016
LA  - ger
PY  - 2016
TI  - Nitroxid-vermittelte Polymerisation mittels NMR-Sonden tragender Initiatoren zur Darstellung von coil-rod-coil-Blockcopolymeren
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:361-29049958
Y2  - 2024-11-22T03:08:06
ER  -