Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-32149 Wissenschaftlicher Artikel Fandrich, Nick; Falkenhagen, Jana; Weidner, Steffen M.; Pfeifer, Dietmar; Staal, Bastiaan; Thuenemann, Andreas F.; Laschewsky, André Characterization of new amphiphilic block copolymers of N-vinyl pyrrolidone and vinyl acetate, 1-analysis of copolymer composition, end groups, molar masses and molar mass distributions New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. C-13 NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, C-13 NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism. 2010 10.1002/macp.200900466 Institut für Chemie OPUS4-32150 Wissenschaftlicher Artikel Fandrich, Nick; Falkenhagen, Jana; Weidner, Steffen M.; Staal, Bastiaan; Thuenemann, Andreas F.; Laschewsky, André Characterization of new amphiphilic block copolymers of N-vinylpyrrolidone and vinyl acetate, 2-chromatographic separation and analysis by MALDI-TOF and FT-IR coupling PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI- TOF MS, our data proved a non-ideal RAFT polymerization. 2010 10.1002/macp.201000044 Institut für Chemie OPUS4-9585 misc Doriti, Afroditi; Brosnan, Sarah M.; Weidner, Steffen M.; Schlaad, Helmut Synthesis of polysarcosine from air and moisture stable N-phenoxycarbonyl-N-methylglycine assisted by tertiary amine base Polysarcosine (Mn = 3650-20 000 g mol−1, Đ ∼ 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator. 2016 3 3067 3070 urn:nbn:de:kobv:517-opus4-95852 Institut für Chemie OPUS4-45818 Wissenschaftlicher Artikel Doriti, Afroditi; Brosnan, Sarah M.; Weidner, Steffen M.; Schlaad, Helmut Synthesis of polysarcosine from air and moisture stable N-phenoxycarbonyl-N-methylglycine assisted by tertiary amine base Polysarcosine (M-n = 3650-20 000 g mol(-1), D similar to 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator. Cambridge Royal Society of Chemistry 2016 4 Polymer Chemistry 7 3067 3070 10.1039/c6py00221h Institut für Chemie OPUS4-46162 Wissenschaftlicher Artikel Wessig, Pablo; Schulze, Tanja; Pfennig, Alexandra; Weidner, Steffen M.; Prentzel, Sascha; Schlaad, Helmut Thiol-ene polymerization of oligospiroketal rods The nucleophilic thiol-ene (thia-Michael) reaction between molecular rods bearing terminal thiols and bis-maleimides was investigated. The molecular rods have oligospiroketal (OSK) and oligospirothioketal (OSTK) backbones. Contrary to the expectations, cyclic oligomers were always obtained instead of linear rigid-rod polymers. Replacing the OS(T)K rods with a flexible chain yielded polymeric products, suggesting that the OS(T) K structure is responsible for the formation of cyclic products. The reason for the preferred formation of cyclic products is due to the presence of folded conformations, which have already been described for articulated rods. Cambridge Royal Society of Chemistry 2017 7 Polymer Chemistry 8 6879 6885 10.1039/c7py01569k Institut für Chemie OPUS4-50906 Wissenschaftlicher Artikel Lüdecke, Nils; Weidner, Steffen M.; Schlaad, Helmut Poly(2-oxazoline)s Based on Phenolic Acids A series of phenolic-acid-based 2-oxazoline monomers with methoxy-substituted phenyl and cinnamyl side chains is synthesized and polymerized in a microwave reactor at 140 °C using methyl tosylate as the initiator. The obtained poly(2-oxazoline)s are characterized by NMR spectroscopy, MALDI-TOF mass spectrometry, and size-exclusion chromatography (SEC). Kinetic studies reveal that the microwave-assisted polymerization is fast and completed within less than ≈10 min for low monomer-to-initiator ratios of ≤25. Polymers with number-average molar masses of up to 6500 g mol−1 and low dispersity (1.2-1.3) are produced. The aryl methyl ethers are successfully cleaved with aluminum triiodide/N,N′-diisopropylcarbodiimide to give a poly(2-oxazoline) with pendent catechol groups. Weinheim Wiley-VCH 2019 5 Macromolecular rapid communications 41 1 10.1002/marc.201900404 Institut für Chemie OPUS4-9584 Wissenschaftlicher Artikel Doriti, Afroditi; Brosnan, Sarah M.; Weidner, Steffen M.; Schlaad, Helmut Synthesis of polysarcosine from air and moisture stable N-phenoxycarbonyl-N-methylglycine assisted by tertiary amine base Polysarcosine (Mn = 3650-20 000 g mol−1, Đ ∼ 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator. Cambridge RSC Publ. 2016 3 Polymer Chemistry 7 3067 3070 10.1039/C6PY00221H Institut für Chemie